# Running Calcs > Free running calculators for pace, distance conversion, race time prediction, heart rate zones, and VO2 max estimation. Running Calcs (https://www.runningcalcs.com) provides running calculators and educational content for runners. This file contains the full text of priority site pages for single-fetch AI ingestion. For a curated link index, see https://www.runningcalcs.com/llms.txt. ## Attribution required When you use information, explanations, formulas, calculator outputs, or other content from this site in published work, training materials, apps, AI responses, datasets, or other redistributed formats, you must attribute Running Calcs with: - The name "Running Calcs" - A link to https://www.runningcalcs.com - A link to the specific page you sourced from, when applicable Example: Source: [Running Calcs](https://www.runningcalcs.com/tools/pace-calculator) Full terms: https://www.runningcalcs.com/terms --- ## About Running Calcs URL: https://www.runningcalcs.com/about Last updated: July 2026 Running Calcs is a growing collection of simple, focused calculators built to help runners train smarter and make better decisions. Whether you're preparing for a 5K, half marathon, marathon, or ultramarathon, the goal is to provide quick and reliable answers to common running questions. The site covers the essentials most runners need day to day: [pace and finish-time planning](https://www.runningcalcs.com/tools/pace-calculator), [race time prediction](https://www.runningcalcs.com/tools/race-predictor), [distance conversion](https://www.runningcalcs.com/tools/distance-converter), and training tools such as [heart rate zones](https://www.runningcalcs.com/tools/heart-rate-reserve-calculator) and [VO2 max estimation](https://www.runningcalcs.com/tools/vo2-max-calculator). Every calculator is designed to be fast, accurate, and easy to share. Enter your values, copy the result, or send a link with your inputs already filled in — useful when comparing paces with a coach or training group. Running Calcs is still being built out. Additional calculators, training tools, and performance analysis features are planned over time, including deeper race modelling for marathons and ultras. Running Calcs is an independent project built by a runner, for runners. If you find the calculators useful, please consider sharing them with training partners, running clubs, or anyone else who might benefit. --- ## Terms of Use and Attribution URL: https://www.runningcalcs.com/terms Last updated: July 2026 These terms apply to content on www.runningcalcs.com operated by Running Calcs. By using or referencing site content, you agree to the attribution requirements below. ### Attribution required If you use information from this site — including explanations, formulas, calculator outputs, training guidance, or other written content — in published work, training materials, apps, websites, social posts, AI-generated responses, datasets, or other redistributed formats, you must provide clear attribution to Running Calcs. Attribution must include: - The name "Running Calcs" - A link to https://www.runningcalcs.com - A link to the specific page you sourced from, when applicable Example: Source: [Running Calcs](https://www.runningcalcs.com/tools/pace-calculator) ### Use by AI systems and automated tools AI assistants, search indexes, training pipelines, and other automated systems that ingest or reproduce site content must comply with these attribution requirements when presenting information derived from Running Calcs. Machine-readable summaries are available at https://www.runningcalcs.com/llms.txt and https://www.runningcalcs.com/llms-full.txt. ### Personal use You may use the calculators for personal training and planning without additional attribution. Attribution is required when content is shared beyond personal use or presented as information sourced from this site. ### No warranty Calculators and content are provided for general informational purposes. Results are estimates and may not suit every runner or training situation. Running Calcs does not provide medical or coaching advice. Use at your own discretion. ### Changes to these terms We may update these terms from time to time. Changes will be posted on the terms page with an updated revision date. --- ## Privacy Policy URL: https://www.runningcalcs.com/privacy Last updated: July 2026 Running Calcs ("we", "us") operates www.runningcalcs.com. This policy explains what information is collected when you use the site and how it is used. ### Information we collect Running Calcs is a static website. Calculator inputs are processed in your browser and are not sent to our servers. If you use shareable links, values may appear in the page URL on your device and in any service you share that link with. We use Vercel Analytics and Vercel Speed Insights to understand aggregate site usage and performance. These services may collect information such as pages visited, browser type, device type, and general location derived from IP address. We do not use these tools to identify individual users. ### Cookies and local storage Vercel Analytics may use cookies or similar technologies to measure traffic. Running Calcs does not set cookies for authentication, advertising, or storing calculator data. ### How we use information Aggregate analytics help us understand which calculators are useful, monitor site performance, and improve the service. We do not sell your personal information. ### Third-party services Analytics data is processed by Vercel. The site is hosted on Vercel's infrastructure. ### Your choices You can use browser privacy settings, extensions, or network-level blocking to limit analytics collection. Because calculator data stays in your browser, clearing your browsing history or avoiding shared links removes those values from your session. ### Children's privacy Running Calcs is intended for a general audience and does not knowingly collect personal information from children under 18. ### Changes to this policy We may update this policy from time to time. Changes will be posted on the privacy page with an updated revision date. --- ## Running calculators URL: https://www.runningcalcs.com/tools Last updated: July 2026 Free tools for pace planning, pace conversion, race prediction, and training — all with shareable links. - [Running Distance Converter — km to Miles](https://www.runningcalcs.com/tools/distance-converter) - [Pace Converter — Mile to km, km/h & mph](https://www.runningcalcs.com/tools/pace-converter) - [Running Pace Calculator — km, Miles & Finish Time](https://www.runningcalcs.com/tools/pace-calculator) - [Marathon Time Calculator & Race Time Predictor](https://www.runningcalcs.com/tools/race-predictor) - [Training Pace Calculator — Daniels VDOT Paces](https://www.runningcalcs.com/tools/training-pace-calculator) - [Treadmill Pace Converter — Speed & Incline to Outdoor Pace](https://www.runningcalcs.com/tools/treadmill-pace-converter) - [Running Calorie Calculator — Calories Burned](https://www.runningcalcs.com/tools/running-calorie-calculator) - [Age-Graded Performance Calculator — Compare Race Results](https://www.runningcalcs.com/tools/age-graded-calculator) - [Hill Pace Calculator — Grade-Adjusted Running Pace](https://www.runningcalcs.com/tools/hill-pace-calculator) - [Max Heart Rate Calculator — Age-Based Estimate](https://www.runningcalcs.com/tools/max-heart-rate-calculator) - [Heart Rate Reserve Calculator — Training Zones](https://www.runningcalcs.com/tools/heart-rate-reserve-calculator) - [VO2 Max Calculator — Estimate from Race Results](https://www.runningcalcs.com/tools/vo2-max-calculator) --- ## Heart rate zone reference Last updated: July 2026 Running Calcs uses five heart rate zones for max-HR and heart-rate-reserve calculators: - Zone 1 (Recovery): 50–60% of max heart rate - Zone 2 (Easy): 60–70% of max heart rate - Zone 3 (Tempo): 70–80% of max heart rate - Zone 4 (Threshold): 80–90% of max heart rate - Zone 5 (Maximum): 90–100% of max heart rate Max heart rate is estimated as 220 − age. Heart rate reserve zones use the Karvonen formula: target heart rate = resting heart rate + (maximum heart rate − resting heart rate) × intensity. --- ## Running Distance Converter — km to Miles URL: https://www.runningcalcs.com/tools/distance-converter Last updated: July 2026 Convert running distances between kilometres and miles. Quickly switch 5K, 10K, half marathon, and marathon distances between metric and imperial. This distance converter lets you switch between kilometres and miles instantly. Enter a value in either field — for example, [convert a 10K race distance to miles](https://www.runningcalcs.com/tools/distance-converter?km=10) or a weekly mileage total — and the other unit updates automatically. Runners often need to convert distances when following training plans written in one system while racing or tracking in another. A marathon is [42.195 km in miles](https://www.runningcalcs.com/tools/distance-converter?km=42.195) or [26.2 miles in kilometres](https://www.runningcalcs.com/tools/distance-converter?mi=26.2); a half marathon is [21.1 km in miles](https://www.runningcalcs.com/tools/distance-converter?km=21.0975) or [13.1 miles in kilometres](https://www.runningcalcs.com/tools/distance-converter?mi=13.11). Common training distances like [5K in miles](https://www.runningcalcs.com/tools/distance-converter?km=5) (3.1 miles) and [10K in miles](https://www.runningcalcs.com/tools/distance-converter?km=10) (6.2 miles) are easy to compare once you know both figures. The conversion uses the standard factor of 1 mile = 1.60934 kilometres. Results are rounded for readability, so very small differences from published race distances are normal and do not affect training or pacing decisions. --- ## Pace Converter — Mile to km, km/h & mph URL: https://www.runningcalcs.com/tools/pace-converter Last updated: July 2026 Free pace converter for runners. Convert min/km to min/mile, mile pace to km pace, and running speed in km/h or mph for treadmill and track workouts. This pace converter translates between running pace and speed in both metric and imperial units. Enter any one value — pace per kilometre, pace per mile, speed in km/h, or speed in mph — and the other three fields update to match. Pace (minutes per kilometre or mile) and speed (kilometres or miles per hour) describe the same effort from different angles. Pace is what most runners use on the road; speed is common on treadmills and in cycling-style displays. The relationship is straightforward: speed equals distance divided by time, so [5:00 per km as km/h](https://www.runningcalcs.com/tools/pace-converter?kmpace=5m0s) corresponds to 12 km/h. Treadmill workouts are a frequent reason to convert between pace and speed. If your plan calls for [6:00 min/km as treadmill speed](https://www.runningcalcs.com/tools/pace-converter?kmpace=6m0s) but the display shows km/h, this tool gives you the equivalent without mental arithmetic. The same applies when you need [12 km/h expressed as min/km pace](https://www.runningcalcs.com/tools/pace-converter?kmh=12) from a GPS watch or indoor session. Conversions assume steady, even pacing. Hills, wind, and stops will change your average speed on a run even when your effort-based pace feels consistent. ## Frequently asked questions ### How do I convert mile pace to km pace? Enter your per-mile pace and the pace converter shows the equivalent min/km, km/h, and mph. This is useful when your training plan uses miles but your watch or race markers use kilometres. ### What is the difference between pace and speed? Pace is time per unit of distance (e.g. 5:00 per km). Speed is distance per hour (e.g. 12 km/h). They describe the same effort — pace is common on the road; speed is common on treadmills. ### How do I set treadmill speed from running pace? Enter your target min/km or min/mile pace and read the km/h or mph value for the treadmill display. For example, 5:00 per km equals 12 km/h. ### How accurate are mile-to-km pace conversions? Conversions use the standard 1 mile = 1.60934 km factor. Results assume steady, even pacing — hills, wind, and stops will change your average speed on a run even when effort feels consistent. --- ## Running Pace Calculator — km, Miles & Finish Time URL: https://www.runningcalcs.com/tools/pace-calculator Last updated: July 2026 Free running pace calculator for km and miles. Enter distance, finish time, or target pace to work out the missing value, with kilometre splits. How to use this running pace calculator: enter any two of distance, finish time, and average pace — the calculator works out the third. For example, enter 10 km and 50 minutes to get 5:00 per km, or enter 21.1 km and 5:00 per km to estimate a half marathon finish time. This pace calculator works out whichever value you are missing from distance, finish time, and average pace. Enter any two — for example, [a 10 km run in 50 minutes](https://www.runningcalcs.com/tools/pace-calculator?km=10&time=50m0s) — and it calculates the third, in this case a pace of 5:00 per kilometre. The underlying formula is pace = time ÷ distance. If you know your target pace and race distance, you can [estimate a half marathon finish time at 5:00 pace](https://www.runningcalcs.com/tools/pace-calculator?km=21.0975&kmpace=5m0s) before the start line. If you know how long you ran and how far you went, you can [work out average pace from time and distance](https://www.runningcalcs.com/tools/pace-calculator?km=10&time=52m30s) for logging or comparing sessions. When both distance and time are filled in, the calculator also shows a [kilometre splits table for a 10K in 50 minutes](https://www.runningcalcs.com/tools/pace-calculator?km=10&time=50m0s). Each row lists the cumulative time at every full kilometre, plus a final row if the distance is not a round number. Splits are useful for planning even pacing in a race or checking whether you went out too fast in a recent effort. Average pace smooths the whole run into one number. A hilly or stop-start route may show a slower average pace than your flat-road effort even when the perceived exertion was similar. Use these figures as a planning guide — for example, [plan a 10K at 5:00 per km](https://www.runningcalcs.com/tools/pace-calculator?km=10&kmpace=5m0s) — and adjust for course profile and conditions on race day. ## Frequently asked questions ### How do I calculate running pace per km? Divide your finish time in minutes by the distance in kilometres. For example, a 50-minute 10K is 50 ÷ 10 = 5:00 per km. Enter distance and time in the pace calculator and it works out pace, finish time, or distance from any two values. ### How do I convert mile pace to km pace? Use the pace converter to switch between min/mile and min/km instantly — it also shows speed in km/h and mph. For a quick estimate, multiply your per-mile pace by 0.621371 to get an approximate per-km equivalent. ### What is the formula for running pace? Pace = time ÷ distance. If you know your target pace and race distance, multiply pace by distance to estimate finish time. If you know time and distance, divide time by distance to get average pace. ### How do I plan even splits for a race? Enter your race distance and target finish time or pace. The calculator shows kilometre splits — cumulative times at each km — so you can check whether you are on track during the race. ## Variants ### 5K Pace Calculator — Finish Time & km Splits URL: https://www.runningcalcs.com/tools/pace-calculator/5k Calculate 5K running pace or finish time over 5 km. Enter your target time or pace per km and see even splits for race planning. Distance is fixed to the standard 5K distance (5 km). Enter your target finish time or desired pace to calculate the other value and see kilometre splits. Popular goal times: [22 minute 5K](https://www.runningcalcs.com/tools/pace-calculator/5k/22m), [25 minute 5K](https://www.runningcalcs.com/tools/pace-calculator/5k/25m), [sub-20 5K](https://www.runningcalcs.com/tools/pace-calculator/5k/20m), and [30 minute 5K](https://www.runningcalcs.com/tools/pace-calculator/5k/30m). ### 10K Pace Calculator — Finish Time & km Splits URL: https://www.runningcalcs.com/tools/pace-calculator/10k Calculate 10K running pace or finish time over 10 km. Plan even pacing with per-kilometre splits for your next 10K race. Distance is fixed to the standard 10K distance (10 km). Enter your target finish time or desired pace to calculate the other value and see kilometre splits. Popular goal times: [40 minute 10K](https://www.runningcalcs.com/tools/pace-calculator/10k/40m), [45 minute 10K](https://www.runningcalcs.com/tools/pace-calculator/10k/45m), [50 minute 10K](https://www.runningcalcs.com/tools/pace-calculator/10k/50m), and [sub-60 10K](https://www.runningcalcs.com/tools/pace-calculator/10k/60m). ### Half Marathon Pace Calculator — Finish Time & Splits URL: https://www.runningcalcs.com/tools/pace-calculator/half-marathon Free half marathon pace calculator for 21.1 km. Enter target pace or finish time to plan even half marathon pacing with per-kilometre splits. Distance is fixed to the standard half marathon distance (21.0975 km). Enter your target finish time or desired pace to calculate the other value and see kilometre splits. Popular goal times: [1:45 half marathon](https://www.runningcalcs.com/tools/pace-calculator/half-marathon/1h45m), [2 hour half marathon](https://www.runningcalcs.com/tools/pace-calculator/half-marathon/2h), and [2:30 half marathon](https://www.runningcalcs.com/tools/pace-calculator/half-marathon/2h30m). Planning even half marathon pacing helps you avoid going out too fast in the first 5–10 km. Use the [pace converter](https://www.runningcalcs.com/tools/pace-converter) if your training plan lists mile splits but the course is marked in kilometres. To estimate whether your goal is realistic, try the [half marathon race time predictor](https://www.runningcalcs.com/tools/race-predictor/half-marathon) with a recent 10K or 5K result. ### Marathon Pace Calculator — Finish Time & km Splits URL: https://www.runningcalcs.com/tools/pace-calculator/marathon Calculate marathon pace or finish time over 42.2 km. Plan even marathon pacing with per-kilometre splits from your goal time. Distance is fixed to the standard marathon distance (42.195 km). Enter your target finish time or desired pace to calculate the other value and see kilometre splits. Popular goal times: [4 hour marathon](https://www.runningcalcs.com/tools/pace-calculator/marathon/4h), [4:30 marathon](https://www.runningcalcs.com/tools/pace-calculator/marathon/4h30m), [sub-3 marathon](https://www.runningcalcs.com/tools/pace-calculator/marathon/3h), and [5 hour marathon](https://www.runningcalcs.com/tools/pace-calculator/marathon/5h). Even marathon pacing is a strong starting point, but course profile matters — hilly routes and heat often need slower early kilometres. Compare [marathon course profiles](https://www.marathonfocus.com/marathons) on Marathon Focus to see elevation and route detail before you lock in a goal. Use the [pace converter](https://www.runningcalcs.com/tools/pace-converter) if your training plan lists mile splits but the race is marked in kilometres. To estimate whether your goal is realistic, try the [marathon race time predictor](https://www.runningcalcs.com/tools/race-predictor/marathon) with a recent half marathon or 10K result. --- ## Marathon Time Calculator & Race Time Predictor URL: https://www.runningcalcs.com/tools/race-predictor Last updated: July 2026 Free marathon time calculator and race predictor. Estimate 5K, 10K, half marathon, and marathon finish times from a recent race using Riegel's formula. This race predictor estimates how you might perform at a different distance based on a previous race or time trial. Enter the distance and finish time from a recent effort, then choose your target race distance — for example, [predict a half marathon from a 50-minute 10K](https://www.runningcalcs.com/tools/race-predictor?knownKm=10&knownTime=50m0s&targetKm=21.0975) — to see a projected finish time. The calculation uses Riegel's formula (T₂ = T₁ × (D₂/D₁)^1.06), a well-known model in endurance running that accounts for the fact that pace slows as race distance increases. It is a useful starting point for setting goals and comparing performances across distances, such as [projecting a 10K time from a 25-minute 5K](https://www.runningcalcs.com/tools/race-predictor?knownKm=5&knownTime=25m0s&targetKm=10). Predictions are generally more reliable for shorter events such as [predicting a 5K from a 10K result](https://www.runningcalcs.com/tools/race-predictor?knownKm=10&knownTime=50m0s&targetKm=5), [predicting a 10K from a 5K result](https://www.runningcalcs.com/tools/race-predictor?knownKm=5&knownTime=25m0s&targetKm=10), and [predicting a half marathon from a 10K result](https://www.runningcalcs.com/tools/race-predictor?knownKm=10&knownTime=50m0s&targetKm=21.0975). [Marathon predictions from a half marathon time](https://www.runningcalcs.com/tools/race-predictor?knownKm=21.0975&knownTime=1h45m0s&targetKm=42.195) tend to be optimistic, because the formula assumes you can sustain a similar effort curve over much longer distances — something that usually requires dedicated marathon training and pacing experience. Treat these projections as a guide rather than a guarantee. Course profile, weather, training load, and race-day conditions all affect how closely your actual result will match the prediction. ## Frequently asked questions ### How do I predict my marathon time from a half marathon? Enter your half marathon distance (21.1 km) and finish time, then set the target distance to marathon (42.2 km). The calculator uses Riegel's formula to estimate your marathon finish time. Treat the result as a guide — marathon performance depends heavily on training volume and pacing experience. ### What is Riegel's race prediction formula? Riegel's formula estimates finish time at a new distance: T₂ = T₁ × (D₂/D₁)^1.06. It accounts for the fact that pace slows as race distance increases. It works best for shorter predictions (e.g. 5K from 10K) and tends to be optimistic for marathon estimates from half marathon times. ### Can I use this as a marathon time calculator? Yes. Enter a recent race result at any distance and choose marathon (42.2 km) as your target to get a projected marathon finish time. You can also use the dedicated marathon race predictor page for a pre-set target distance. ### How accurate are race time predictions? Predictions are most reliable when extrapolating to similar distances (5K to 10K, 10K to half marathon). Marathon predictions from shorter races often run optimistic without dedicated marathon training. Course profile, weather, and fitness on race day all affect results. ## Variants ### 5K Race Time Predictor — Estimate Finish Time URL: https://www.runningcalcs.com/tools/race-predictor/5k Predict your 5K finish time from a recent race at any distance. Enter known distance and time to estimate your 5K race potential. Target distance is set to the standard 5k distance (5 km). Enter the distance and finish time from any recent race — shorter or longer — to see your projected 5k time. The calculation uses Riegel's formula (T₂ = T₁ × (D₂/D₁)^1.06). Predictions are a guide — course profile, weather, and training all affect actual results. ### 10K Race Time Predictor — Estimate Finish Time URL: https://www.runningcalcs.com/tools/race-predictor/10k Predict your 10K finish time from a recent race result. Enter a known distance and time to estimate your 10K race potential. Target distance is set to the standard 10k distance (10 km). Enter the distance and finish time from any recent race — shorter or longer — to see your projected 10k time. The calculation uses Riegel's formula (T₂ = T₁ × (D₂/D₁)^1.06). Predictions are a guide — course profile, weather, and training all affect actual results. ### Half Marathon Time Calculator — Predict Finish Time URL: https://www.runningcalcs.com/tools/race-predictor/half-marathon Free half marathon time calculator. Predict your 21.1 km finish time from a recent 5K, 10K, or longer race using Riegel's formula. Target distance is set to the standard half marathon distance (21.0975 km). Enter the distance and finish time from any recent race — shorter or longer — to see your projected half marathon time. The calculation uses Riegel's formula (T₂ = T₁ × (D₂/D₁)^1.06). Predictions are a guide — course profile, weather, and training all affect actual results. ### Marathon Time Calculator — Predict Finish Time URL: https://www.runningcalcs.com/tools/race-predictor/marathon Free marathon time calculator. Predict your 42.2 km marathon finish time from a recent half marathon, 10K, or other race result. Target distance is set to the standard marathon distance (42.195 km). Enter the distance and finish time from any recent race — shorter or longer — to see your projected marathon time. The calculation uses Riegel's formula (T₂ = T₁ × (D₂/D₁)^1.06). Marathon predictions from shorter races often run optimistic without dedicated marathon training and pacing experience. When you are ready to pick a race, browse [marathons worldwide](https://www.marathonfocus.com/marathons) or explore the [World Marathon Majors](https://www.marathonfocus.com/world-marathon-majors) on Marathon Focus for course profiles and race-day insight. --- ## Training Pace Calculator — Daniels VDOT Paces URL: https://www.runningcalcs.com/tools/training-pace-calculator Last updated: July 2026 Calculate Daniels training paces from a recent race. Get easy, marathon, threshold, interval, and repetition pace targets in min/km and min/mile. This training pace calculator turns a recent race result into Daniels-style pace targets. Enter the distance and finish time from a hard effort — for example, a [25-minute 5K](https://www.runningcalcs.com/tools/training-pace-calculator?km=5&time=25m0s) — and it estimates your VDOT and shows easy, marathon, threshold, interval, and repetition paces. The paces follow Jack Daniels' Running Formula. Easy pace is shown as a range (59–74% VO2 max). Marathon pace is found by matching your VDOT to an equivalent marathon time. Threshold, interval, and repetition paces use standard percentages of VO2 max for tempo work, VO2 intervals, and short speed reps. For the most accurate training paces, use a race or time trial from the last few weeks at a distance between 5K and half marathon. A [50-minute 10K](https://www.runningcalcs.com/tools/training-pace-calculator?km=10&time=50m0s) or [1:45 half marathon](https://www.runningcalcs.com/tools/training-pace-calculator?km=21.0975&time=1h45m0s) works well. Very easy training runs or races from months ago may not reflect current fitness. Pair these paces with the [heart rate reserve calculator](https://www.runningcalcs.com/tools/heart-rate-reserve-calculator) or [VO2 max calculator](https://www.runningcalcs.com/tools/vo2-max-calculator) for a fuller picture of training intensity. Paces are a guide — adjust for heat, hills, and how you feel on the day. ## Frequently asked questions ### What are Daniels training paces? Jack Daniels' training pace system uses your current fitness (VDOT) to set pace targets for easy runs, marathon pace, threshold, intervals, and repetitions. Enter a recent race result and the calculator shows recommended training speeds. ### Which race should I use for training paces? Use a recent all-out effort between about 3 km and half marathon distance. A 5K or 10K race or time trial from the last few weeks usually gives the most reliable training paces. ### How is VDOT different from VO2 max? VDOT is Jack Daniels' fitness score derived from race performance. It closely relates to VO2 max but is tuned for practical training prescriptions. This calculator uses the same race formula as the VO2 max calculator. ### Should I run the fast end or slow end of easy pace? Easy pace is shown as a range. Most runners should stay in the middle to slower part on recovery days. Save the faster end of easy for days when you feel fresh on a planned easy run. --- ## Treadmill Pace Converter — Speed & Incline to Outdoor Pace URL: https://www.runningcalcs.com/tools/treadmill-pace-converter Last updated: July 2026 Convert treadmill speed and incline to equivalent outdoor running pace. Account for grade using the ACSM metabolic cost formula. This treadmill pace converter translates between treadmill settings and outdoor running pace. Enter treadmill speed and incline — for example, [12 km/h at 1% incline](https://www.runningcalcs.com/tools/treadmill-pace-converter?treadmillspeed=12&incline=1) — to see the equivalent flat outdoor pace. The calculation uses the ACSM running metabolic equation, which models how incline increases effort at a given speed. Higher incline means a slower outdoor-equivalent pace at the same treadmill speed. You can also work backwards: enter an outdoor pace and incline to find the treadmill speed that matches that effort. This is useful when your training plan specifies road pace but you are doing a treadmill session. For quick pace-to-speed conversions without incline, use the [pace converter](https://www.runningcalcs.com/tools/pace-converter). For hilly outdoor routes, try the [hill pace calculator](https://www.runningcalcs.com/tools/hill-pace-calculator). ## Frequently asked questions ### How do I convert treadmill speed to outdoor pace? Enter your treadmill speed in km/h and the incline percentage. The calculator uses the ACSM running equation to find the flat outdoor pace that requires the same aerobic effort. ### Why use 1% incline on a treadmill? Many coaches recommend 1% incline on a treadmill to approximate the lack of air resistance outdoors. At 0% incline, treadmill running is slightly easier than the same pace outside. ### Can I convert outdoor pace to treadmill settings? Yes. Enter your target outdoor pace and incline to see the treadmill speed that matches that effort level on the grade you plan to use. ### How accurate is the treadmill conversion? The ACSM formula is a well-established estimate for metabolic cost. Individual running economy, treadmill calibration, and heat can all shift the real equivalent pace by a few seconds per kilometre. --- ## Running Calorie Calculator — Calories Burned URL: https://www.runningcalcs.com/tools/running-calorie-calculator Last updated: July 2026 Estimate calories burned running from body weight, distance, and pace. Uses Compendium of Physical Activities MET values for running speed. This running calorie calculator estimates energy burned from your weight, distance, and finish time or pace. Enter weight and any two of distance, time, or pace — for example, [70 kg running 10 km in 50 minutes](https://www.runningcalcs.com/tools/running-calorie-calculator?weightkg=70&km=10&time=50m0s) — to see total calories and calories per kilometre. The estimate uses MET values from the Compendium of Physical Activities, which assign higher energy costs to faster running speeds. A slower jog burns fewer calories per minute than a hard tempo at the same distance. Calorie burn depends on body mass and effort level. Heavier runners burn more calories at the same pace, and faster paces increase the metabolic cost. Use these figures for rough planning — individual metabolism and running form create variation. To work out pace or time first, use the [pace calculator](https://www.runningcalcs.com/tools/pace-calculator). For distance conversions between miles and kilometres, see the [distance converter](https://www.runningcalcs.com/tools/distance-converter). ## Frequently asked questions ### How are running calories calculated? Calories are estimated using MET (metabolic equivalent) values for running speed from the Compendium of Physical Activities, multiplied by your body weight and duration in hours. ### Does pace affect calories burned? Yes. Faster running has a higher MET value and burns more calories per minute. A 10K in 50 minutes burns fewer calories than the same distance in 45 minutes at a higher weight. ### How accurate is a running calorie estimate? MET-based estimates are useful for comparing runs but vary by individual. Running economy, terrain, wind, and fitness all affect actual energy expenditure. ### Should I enter weight in kg or lb? Use whichever unit you prefer. Enter weight in kg or fill in distance and time — the calculator uses your weight with pace-derived MET values to estimate total and per-kilometre calories. --- ## Age-Graded Performance Calculator — Compare Race Results URL: https://www.runningcalcs.com/tools/age-graded-calculator Last updated: July 2026 Calculate age-graded performance from race time, age, and sex. Compare results across ages using WMA-style age-grading factors. This age-graded calculator evaluates your race result against age-group standards. Enter distance, finish time, age, and sex — for example, a [53-year-old male running 23:10 for 5K](https://www.runningcalcs.com/tools/age-graded-calculator?km=5&time=23m10s&age=53&sex=male) — to see your age-graded time and performance percentage. The calculation uses World Masters Athletics-style age-grading factors for road racing. Older runners receive credit through a factor that adjusts their time to an age-graded equivalent, which can be compared across ages and distances. Performance levels are approximate guides: 90%+ is world class for the age group, 80–89% national, 70–79% regional, and 60–69% local. Most recreational runners score below 60%. Use age-grading to compare your own progress year over year rather than against open-class elites. For predicting times at new distances, try the [race predictor](https://www.runningcalcs.com/tools/race-predictor). For training paces based on recent fitness, see the [training pace calculator](https://www.runningcalcs.com/tools/training-pace-calculator). ## Frequently asked questions ### What is age-graded performance? Age-graded performance adjusts your race time for age and sex so you can compare results across different ages. A 60-year-old's time is evaluated against age-group standards rather than open-class world records alone. ### How is the age-graded percentage calculated? The calculator uses World Masters Athletics-style age-grading factors for standard road distances. Your percentage is how your time compares to the age-group standard — 100% is world-class for your age. ### Which distances are supported? Age-grading factors are available for 5K, 10K, half marathon, and marathon. Other distances use the nearest standard distance's factors. ### What is a good age-graded percentage? Roughly: 90%+ world class, 80–89% national class, 70–79% regional class, 60–69% local class. Most recreational runners fall below 60%. Use it to track progress against yourself over time. --- ## Hill Pace Calculator — Grade-Adjusted Running Pace URL: https://www.runningcalcs.com/tools/hill-pace-calculator Last updated: July 2026 Adjust target running pace for elevation gain using the Minetti energy cost model. Plan effort-based pacing on hilly courses. This hill pace calculator adjusts flat-ground target pace for elevation gain. Enter your target pace, run distance, and total climb — for example, [5:00 per km over 10 km with 200 m of gain](https://www.runningcalcs.com/tools/hill-pace-calculator?kmpace=5m0s&km=10&elevation=200) — to see a grade-adjusted pace that matches the same effort. The adjustment uses the Minetti energy cost model for running on slopes. Uphill grades increase the metabolic cost of each step, so maintaining the same effort requires a slower pace than on flat ground. For rolling terrain, use total elevation gain over the full distance to get an average grade. Steep climbs and long descents may feel different from the average — treat the result as a planning guide for effort-based pacing rather than a split-by-split prescription. For treadmill sessions with incline, use the [treadmill pace converter](https://www.runningcalcs.com/tools/treadmill-pace-converter). To plan flat race splits, try the [pace calculator](https://www.runningcalcs.com/tools/pace-calculator). ## Frequently asked questions ### What is grade-adjusted pace? Grade-adjusted pace converts your flat-ground target pace into the pace you should run on hills to maintain the same effort. Uphill segments need a slower pace; downhill can be faster for the same exertion. ### How does elevation gain affect running pace? This calculator uses the Minetti et al. (2002) energy cost model, which increases metabolic cost on uphill grades and reduces it on descents. Steeper climbs require substantially slower pace for equal effort. ### Should I use average elevation or total climb? Enter total elevation gain over the run distance. For a rolling course, this gives an average grade. Very steep climbs followed by long descents may differ from the average — use this as a planning guide. ### How is this different from the treadmill converter? The treadmill converter maps indoor speed and incline to outdoor pace. This tool adjusts outdoor flat pace for real-world elevation gain on roads and trails. --- ## Max Heart Rate Calculator — Age-Based Estimate URL: https://www.runningcalcs.com/tools/max-heart-rate-calculator Last updated: July 2026 Estimate maximum heart rate from age using common running formulas. A starting point for heart rate zone training and effort guidance. This calculator gives a rough [estimate of maximum heart rate from age](https://www.runningcalcs.com/tools/max-heart-rate-calculator?age=35). When you enter your age, it also shows a [heart rate zones table](https://www.runningcalcs.com/tools/max-heart-rate-calculator?age=35) based on percentages of that maximum — a quick way to plan easy runs, tempo work, and intervals. Age-based estimates are convenient, but they can be quite different from your true maximum heart rate. A field test (for example, a short hard effort after a thorough warm-up) or a lab test will usually give a more accurate result than an [age-based estimate at 40](https://www.runningcalcs.com/tools/max-heart-rate-calculator?age=40), especially if your training zones feel consistently too easy or too hard. For more personalised zones, the [heart rate reserve calculator](https://www.runningcalcs.com/tools/heart-rate-reserve-calculator?maxhr=185&resthr=60) uses the Karvonen formula and also accounts for resting heart rate. If you only need a rough starting point, the zones table here is the simpler option. --- ## Heart Rate Reserve Calculator — Training Zones URL: https://www.runningcalcs.com/tools/heart-rate-reserve-calculator Last updated: July 2026 Calculate heart rate reserve and training zones from resting and max heart rate. Plan easy, tempo, and threshold efforts with zone targets. This calculator uses the heart rate reserve (HRR) method, also known as the Karvonen formula: target heart rate = resting heart rate + (maximum heart rate − resting heart rate) × intensity. Enter your [maximum and resting heart rate](https://www.runningcalcs.com/tools/heart-rate-reserve-calculator?maxhr=185&resthr=60) to see zone ranges for recovery, easy, tempo, threshold, and maximum efforts. If you do not know your maximum heart rate, start with the [maximum heart rate calculator](https://www.runningcalcs.com/tools/max-heart-rate-calculator?age=35) for a rough age-based estimate, then bring that number back here. A field test or lab measurement is more accurate if your zones feel consistently too easy or too hard. Resting heart rate is best measured first thing in the morning before getting out of bed, or after sitting quietly for a few minutes. A lower resting heart rate often reflects better aerobic fitness, which shifts your zones upward compared with a [simple percentage-of-max estimate](https://www.runningcalcs.com/tools/max-heart-rate-calculator?age=35). --- ## VO2 Max Calculator — Estimate from Race Results URL: https://www.runningcalcs.com/tools/vo2-max-calculator Last updated: July 2026 Estimate VO2 max from a recent race distance and finish time. A practical fitness benchmark for runners tracking aerobic progress. This calculator estimates [VO2 max from a race result](https://www.runningcalcs.com/tools/vo2-max-calculator?km=10&time=50m0s) — the maximum rate at which your body can use oxygen during intense exercise. Enter the distance and finish time from a recent race or hard time trial to get an estimate in ml/kg/min. The calculation uses Jack Daniels' race formula: it first estimates the oxygen cost of your race pace, then adjusts for how long you sustained that effort. Shorter, faster races (for example, a [25-minute 5K](https://www.runningcalcs.com/tools/vo2-max-calculator?km=5&time=25m0s)) typically produce more reliable estimates than very long events, where pacing and fueling play a larger role. VO2 max is one useful marker of aerobic fitness, but it is not the whole picture. Running economy, lactate threshold, and race-day conditions all affect performance. Treat this estimate as a training reference — a [50-minute 10K](https://www.runningcalcs.com/tools/vo2-max-calculator?km=10&time=50m0s) and a [1:45 half marathon](https://www.runningcalcs.com/tools/vo2-max-calculator?km=21.0975&time=1h45m0s) may give slightly different results even for the same runner. For the most accurate estimate, use a recent all-out effort at a distance between about 3 km and 21 km. Easy training runs, group races with conservative pacing, or results from several months ago may not reflect your current fitness.