Quick answer
Pace = finish time ÷ distance. A 4:00:00 marathon (42.195 km) needs a pace of 5:41 per km, or 9:09 per mile.
Choose a race, enter a target finish time. The calculator returns the pace per kilometre and per mile.
Related tools: Pace Distance Calculator: Distance covered at a steady pace for a given time. Race Time Prediction Calculator: Predict a finish time at another distance with Riegel's formula. Running Training Pace Calculator: Estimate VO₂max (VDOT) from a race result and get easy, threshold and interval training paces.
How to use the Marathon Pace Calculator
- Choose race: Marathon (42.195 km), Half marathon (21.0975 km), 10K and 5K.
- Optionally, enter hours (0 or more).
- Optionally, enter minutes (0 or more).
- Optionally, enter seconds (0 or more).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Race | Choose one: Marathon (42.195 km); Half marathon (21.0975 km); 10K; 5K | Starts at Marathon (42.195 km) |
| Hours (optional) | A number | ≥ 0 |
| Minutes (optional) | A number | ≥ 0 |
| Seconds (optional) | A number | ≥ 0 |
Formula and method
Formula
pace = finish time ÷ race distance
IEEE-754 double precision; shown to the decimals indicated.
Official road-race distances: marathon 42.195 km, half marathon 21.0975 km. Informational estimate, not medical advice. Talk to a qualified health professional about your own situation.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Race = Marathon (42.195 km); Hours = 4; Minutes = 0; Seconds = 0.
| Result | Value |
|---|---|
| Pace per km | 5:41 |
| Pace per mile | 9:09 |
Example 2
Inputs: Race = Half marathon (21.0975 km); Hours = 1; Minutes = 45; Seconds = 0.
| Result | Value |
|---|---|
| Pace per km | 4:59 |
| Pace per mile | 8:01 |
Example 3
Inputs: Race = 10K; Hours = 0; Minutes = 48; Seconds = 30.
| Result | Value |
|---|---|
| Pace per km | 4:51 |
| Pace per mile | 7:48 |
The first line is the headline result (pace per km). Below it the marathon Pace Calculator lists pace per mile, which describe the same case from other angles. IEEE-754 double precision; shown to the decimals indicated.
Working it out
4 hours is 14,400 seconds; ÷ 42.195 km = 341.3 s per km, i.e. 5:41. Per mile (1.609 km) that is 549 s = 9:09. A sub-4 marathon needs a pace slightly faster than 9:09 per mile.
Race strategy
Even pacing or a slight negative split usually works best. Start no faster than goal pace; hitting the half-way mark at 2:00:00 for a 4:00 finish is typical. Weather and the course profile change the effort needed.
How the result changes with hours
Holding every other input at the first worked example, this table changes only hours. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Hours | Pace per km | Pace per mile |
|---|---|---|
| 2 | 2:51 | 4:35 |
| 4 | 5:41 | 9:09 |
| 8 | 11:23 | 18:18 |
| 16 | 22:45 | 36:37 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Minutes: entering "0" shows "Enter a time greater than zero." beside that field and no result.
- Hours: entering "-1" shows "Hours must be at least 0." beside that field and no result.
Choosing between the Marathon Pace Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Pace Distance Calculator](/fitness/pace-distance-calculator/) | pace minutes and pace per | Distance |
| [Race Time Prediction Calculator](/fitness/race-time-prediction-calculator/) | known race distance, unit and target distance | Predicted time |
| [Running Training Pace Calculator](/fitness/training-pace-calculator/) | race distance, hours and minutes | VDOT (estimated VO₂max) |
| [Pace Calculator](/fitness/pace-calculator/) | distance and distance unit | Pace per km |
| [Calories per Mile Calculator](/fitness/calories-per-mile-calculator/) | body weight and pace | Calories per mile |
Background: fitness estimates
Fitness formulas are estimates whose accuracy depends on the input. One-rep-max formulas such as Epley and Brzycki give different answers, and predictions from hard sets of a few repetitions are better than from sets of ten or more. Age-based maximum heart rate formulas can be off by 10 to 30 beats a minute for an individual; Tanaka's 208 − 0.7 × age is generally preferred to 220 − age but is still an estimate.
Pace models built from a race result assume a maximal effort and work best for distances from about 5 km to the marathon. Use the output as a guide, not a prescription.
Assumptions and limitations
- Time can be entered in any combination of hours, minutes and seconds
- Not a diagnosis
Estimates from formulas describe averages. They are not a training or medical prescription; check with a qualified professional before changing your exercise or diet.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for minutes and hours to confirm this.
Frequently asked questions
What pace is a 3:30 marathon?
A 3:30 marathon needs about 4:58 per km (8:00 per mile).
What is a negative split?
Running the second half faster.
Should I run the whole thing at pace?
Aim for steady effort.
What does the Marathon Pace Calculator calculate?
Pace needed to finish a race distance in a target time. It returns Pace per km and Pace per mile.
What formula does the Marathon Pace Calculator use?
pace = finish time ÷ race distance. Official road-race distances: marathon 42.195 km, half marathon 21.0975 km.
What do I need to enter in the marathon Pace Calculator?
You enter Race. Optional: Hours, Minutes and Seconds.
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Time can be entered in any combination of hours, minutes and seconds.
What are the limits of this calculator?
Time can be entered in any combination of hours, minutes and seconds. Not a diagnosis.
What does the “Race” option change?
It sets how the marathon Pace is worked out. The choices are Marathon (42.195 km), Half marathon (21.0975 km), 10K and 5K.
What is an example of a marathon Pace result?
With race Marathon (42.195 km), hours 4, minutes 0 and seconds 0, the pace per km is 5:41.
Where does the method come from?
The method follows: World Athletics road-running distances; International mile: 1,609.344 m exactly (1959 International Yard and Pound Agreement).
Can I rely on this calculator for a decision?
Estimates from formulas describe averages. They are not a training or medical prescription; check with a qualified professional before changing your exercise or diet. For this calculator in particular: Time can be entered in any combination of hours, minutes and seconds.
Related calculators
- Pace Distance Calculator — Distance covered at a steady pace for a given time.
- Race Time Prediction Calculator — Predict a finish time at another distance with Riegel's formula.
- Running Training Pace Calculator — Estimate VO₂max (VDOT) from a race result and get easy, threshold and interval training paces.
- Pace Calculator — Pace and speed from a distance and a time.
- Calories per Mile Calculator — Energy cost of running a mile from body weight and pace (ACSM equation).
- Swimming Pace Calculator — Pace per 100 meters or yards from a distance and a time.
Sources
- World Athletics road-running distances; International mile: 1,609.344 m exactly (1959 International Yard and Pound Agreement)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.