Running calculators
Free calculators for runners. Turn a goal time into a pace, predict your time over another distance, get your VDOT training paces, find your Zone 2 heart rate, plan race-week carbs and check whether your running shoes are done. Every tool shows its formula, a worked example and what the result means for your training.
Pace and race times
Paces, splits, finish times and the paces to train at.
Pace, time or distance for any run, converted between min/km, min/mile, km/h and mph.
Open calculator →Goal marathon or half marathon time into pace, 5 km splits and a negative-split plan.
Open calculator →Predict 5K to marathon times from one recent race, with Riegel and VDOT side by side.
Open calculator →Your VDOT from a recent race, with easy, marathon, threshold, interval and repetition paces.
Open calculator →Swim pace, bike speed, run pace and transitions turned into splits and a finish time, sprint to full distance.
Open calculator →Plan your training
How many weeks you need, and how hard each run should feel.
Heart rate and recovery
Max heart rate, Zone 2, resting heart rate, HRV, rest days and breaks.
Your estimated maximum heart rate from five age formulas, and how to find your real one.
Open calculator →Your Zone 2 in heart rate and watts, from threshold heart rate, max heart rate or FTP.
Open calculator →Normal resting heart rate by age and sex, and whether today’s reading is normal for you.
Open calculator →Typical HRV (RMSSD) for your age and sex, and whether today’s HRV is normal for you.
Open calculator →A quick check of sleep, heart rate, legs and mood that says train, go easy or rest.
Open calculator →How much fitness you lose during a break, and how long it takes to get it back.
Open calculator →The neck check: when easy training is fine, when to rest and when to see a doctor.
Open calculator →Fuel, race day and shoes
Carb loading, caffeine, sweat rate, race-day packing and shoe wear.
Grams of carbohydrate per day before a long race, split into meals with food examples.
Open calculator →A safe, effective pre-race caffeine dose from your weight, with timing and the sleep cut-off.
Open calculator →Weigh in before and after a ride to find your sweat rate per hour and how much to drink.
Open calculator →A printable packing list for road, gran fondo, TT, gravel, MTB, running and triathlon races.
Open calculator →How long running shoes last, the signs they are done, and a kilometre estimate for your pair.
Open calculator →Also on the bike?
FTP, watts per kg, tire pressure, gearing and bike maintenance tools are on the cycling calculators page.
See the cycling calculators →What these calculators are for
A goal time means little until it becomes a pace. A pace means little until you know whether you can hold it, and what to run in training to get there. Each calculator on this page turns one running question into a number you can use: a pace per kilometre or mile, a predicted finish time, a set of training paces, a heart rate zone or a race-week carbohydrate target.
Every tool shows the formula it uses, a worked example and what the result means for your training, so you can check the logic instead of trusting a black box. You do not need an account, and the numbers you type are never sent to us.
Five tools here are built only for runners: pace, marathon pace, race time prediction, VDOT and running shoes. The others, such as the heart rate, recovery and fuel tools, are shared with the LeCoach cycling calculators, because the physiology behind them is the same in both sports.
Which calculator answers which question
Pace and race times
| Your question | Use this calculator | What you get |
|---|---|---|
| What pace is this run? | Running pace calculator | Pace, time or distance in every unit, with splits |
| What pace do I need for my marathon goal? | Marathon pace calculator | Pace, 5 km splits and a negative-split plan |
| What could I run over another distance? | Race time predictor | 1500 m to marathon predictions, two methods |
| What paces should I train at? | VDOT calculator | VDOT and five training paces |
| What will my triathlon finish time be? | Triathlon pace calculator | All five splits and your finish time |
Plan your training
| Your question | Use this calculator | What you get |
|---|---|---|
| How long do I need to train for my race? | How long to train calculator | Weeks needed from your longest recent run |
| How hard did that run feel, in numbers? | RPE scale | RPE 1 to 10 matched to zones, and session load |
Heart rate and recovery
| Your question | Use this calculator | What you get |
|---|---|---|
| What is my max heart rate? | Max heart rate calculator | Five age formulas compared, and how to find your real max |
| What is my Zone 2? | Zone 2 heart rate calculator | Zone 2 in beats per minute, plus the talk test |
| Is my resting heart rate normal? | Resting heart rate by age | Norms by age and a check against your own baseline |
| Is my HRV good? | HRV by age | Typical HRV for your age and a daily check |
| Do I need a rest day? | Rest day check | Train, go easy or rest, from today's signs |
| How much fitness will I lose on a break? | Detraining calculator | Fitness loss and the time to rebuild |
| Can I run with a cold? | Training with a cold | The neck check: easy, rest or see a doctor |
Fuel, race day and shoes
| Your question | Use this calculator | What you get |
|---|---|---|
| How do I carb load? | Carb loading calculator | Grams per day, split into meals with food examples |
| How much caffeine before a race? | Caffeine calculator | Dose, timing and the sleep cut-off |
| How much do I sweat? | Sweat rate calculator | Litres per hour and a drinking target |
| What do I need to pack? | Race day checklist | Printable list for your race and the weather |
| Do I need new running shoes? | When to replace running shoes | The rule, the signs and kilometres left |
How the calculators fit together
Most of these numbers depend on each other, so the order you use them in matters.
1. Start from a recent race. A real result tells you more than any formula. Enter it in the VDOT calculator to get your VDOT and five training paces, or in the race time predictor to see what it means over other distances.
2. Set a goal you can train for. The marathon pace calculator turns a goal time into a pace and splits. If your predicted time and your goal time are far apart, the how long to train calculator shows how many weeks you need from your current long run.
3. Keep the easy runs easy. Most of your weekly running should be easy. The Zone 2 heart rate calculator and the RPE scale tell you what easy means in beats per minute and in feel. If you do not know your maximum heart rate, start with the max heart rate calculator.
4. Absorb the miles. Fitness is built in the days after the run, not during it. A resting heart rate a few beats above your normal, or an HRV well below it, is an early sign to ease off: compare yours with the resting heart rate and HRV checkers, and let the rest day check decide when you are unsure. A niggle that needs a week off costs less than you think; the detraining calculator shows how much.
5. Prepare race week. Plan your carbohydrate with the carb loading calculator, your pre-race coffee with the caffeine calculator and your drinking with the sweat rate calculator. Then pack with the race day checklist and print your splits from the running pace calculator.
6. Look after your shoes. Worn-out cushioning is easy to miss. The running shoe checker gives the rule, the signs to look for and an estimate of the kilometres left in your pair.
Calculators versus a coach
A pace calculator tells you what 3:30 for a marathon means per kilometre. It cannot tell you whether you are on track for it. Your threshold pace moves as you train, a hot week changes what easy feels like, and two hard runs might be one too many after a bad night's sleep.
That is the gap LeCoach fills. It reads your runs and your wellness data (HRV, sleep and resting heart rate) from Intervals.icu, builds your running plan with paces from your own threshold pace, and explains each suggested change instead of reshuffling your week in the background. You can also ask it the same questions these calculators answer, and it answers from your own data.
How accurate are these numbers?
The running tools use well-tested models, such as Daniels' VDOT tables and the Riegel formula, and every page names its source. They are consistent, but they describe a typical runner on a good day. Three things decide how close they get for you:
- The quality of your input. A recent, well-paced race gives far better predictions and training paces than an old result or a training run.
- The gap between distances. Predictions are best between nearby distances. From a 5K to a marathon the error grows, and it grows most if your long runs are short.
- The conditions. Heat, hills, wind and altitude all slow you down. The calculators assume a flat course in good weather.
So treat a prediction as a target to test, not a promise: race or time-trial every few months and update your paces from the new result.
Sources
- Daniels J. Daniels' Running Formula, 4th edition. Human Kinetics, 2022.
- Daniels J, Gilbert J. Oxygen Power: Performance Tables for Distance Runners. 1979.
- Riegel PS. Athletic records and human endurance. American Scientist, 1981;69(3):285-290.
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 2001;37(1):153-156.
- Ely MR et al. Impact of weather on marathon-running performance. Medicine and Science in Sports and Exercise, 2007;39(3):487-493.
- Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine joint position statement: nutrition and athletic performance. Medicine and Science in Sports and Exercise, 2016;48(3):543-568.
Frequently asked questions
Are these running calculators free?
Yes, all of them, with no account and no sign-up. Everything is worked out in your browser, so your times and paces are never sent to us. If you would rather have your paces and plan worked out from your own runs, LeCoach has a 14-day free trial without a credit card.
Which running calculator should I use first?
Start with the VDOT calculator and a recent race result. It gives you both a fitness number and the five paces to train at. If you have no recent race, run a 5K time trial on a flat route and use that.
How do I calculate my running pace?
Divide your time by the distance. A 10 km run in 50 minutes is 5:00 per kilometre, or 8:03 per mile. The running pace calculator does this for any distance and also works backwards, from a pace to a finish time.
How accurate is a race time predictor?
For distances close to your race, predictions are usually within 1 to 3 %. For much longer distances, especially the marathon, they are often optimistic by 5 % or more unless you have trained specifically for the longer distance. A half marathon result predicts a marathon better than a 5K does.
Do I need a heart rate monitor?
No. Pace and how a run feels are enough to train well, and the RPE scale shows how to put a number on feel. A heart rate monitor helps most on easy days, when it stops you drifting into a pace that is too hard.
Why are some tools shared with the cycling calculators?
Heart rate, recovery and fuel work the same way whether you run or ride. Those pages sometimes use cycling examples, but the numbers and the advice apply to runners too.
How is LeCoach different from these calculators?
A calculator works from the numbers you type in, once. LeCoach is an AI coach for runners and cyclists that reads your runs and recovery data from Intervals.icu every day, builds your plan back from your race date, writes every session at your own paces and tells you when and why something should change. You can also ask it anything about your running.
From race time to training plan
Get an AI coach that builds your running plan back from race day, with every run written at the right pace.
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