Race Pace Calculator
Turn a goal time for 5 km, 10 km, a half marathon or a marathon into the pace per kilometer and per mile, the speed, and even splits.
The pace you need to hold for your goal time, with the splits.
How the race pace calculator works
Pace is time divided by distance. Pick the race (or type a custom distance in Detailed mode), enter the finish time you want, and the calculator gives the pace per kilometer and per mile, the average speed, and where you should be at 5 km, 10 km and halfway if you run even splits.
Even splits are the most economical way to race; most runners who miss a goal went out too fast. Use the 5 km split as a check in the first minutes of the race.
Formula: pace = time ÷ distance
Worked examples
| Inputs | Pace per kilometer | Note |
|---|---|---|
| 10 km in 50:00 | 5:00 /km | 5:00 /km, 8:03 /mi |
| Half marathon in 1:59:59 | 5:41 /km | the sub-2 pace: 5:41 /km |
| Marathon in 3:30:00 | 4:59 /km | 4:59 /km |
| 5 km in 25:00 | 5:00 /km | 5:00 /km |
FAQFrequently asked questions
What pace do I need for a sub-2-hour half marathon?
Under 5:41 per kilometer (9:09 per mile) for the full 21.1 km. Aim for 5:38 to leave a small margin.
How should I split the race?
Evenly, or very slightly faster in the second half. Going out 15 seconds per kilometer too fast usually costs more than that later.
Why does my watch show a different pace?
GPS usually measures a race slightly long — corners and weaving add distance — so the watch pace reads faster than the official one. Trust the course splits.
How do I convert pace between km and miles?
Multiply a per-kilometer pace by 1.609 to get the per-mile pace, or divide to go the other way. 5:00 /km is 8:03 /mi.
Where these figures come from
- Riegel PS, "Athletic records and human endurance", American Scientist 1981 — T2 = T1 × (D2 ÷ D1)^1.06
- Cooper KH, "A means of assessing maximal oxygen intake", JAMA 1968 — the 12-minute run test
- Ainsworth BE et al., Compendium of Physical Activities (2024 update) — MET values by activity
- OpenPowerlifting — DOTS coefficients (Tim Konertz, 2019) — the DOTS polynomial used for scoring
- Naismith's rule (1892) as used by UK and Australian walking bodies — 1 hour per 5 km plus 1 hour per 600 m of ascent
- American College of Sports Medicine — exercize-science guidelines
Last checked: September 2026. Formulas are fixed by their published sources; the MET values come from the Compendium of Physical Activities.