---
title: "Running Pace Calculator: per km & per mile | Run Pebble"
description: "Enter any two of distance, time and pace to get the third, in km and miles, with speed and finish times for 5K, 10K, half marathon and marathon."
url: https://runpebble.me/
---

Kilometres and miles, side by side

# Running pace calculator

Fill in two of distance, time and pace, and get the third, with your speed and finish times for the big race distances.

## How the pace calculator works

Choose what to work out, then fill in the other two boxes. Pace is time per kilometre or per mile: change the unit beside the box and everything else follows. The result shows pace both ways, your speed in km/h and mph, and how long 5K, 10K, a half marathon and a marathon take at that pace.

- **Times** can be typed as 55:00, 1:05:30 or 3:59:59. A single number counts as minutes, and 1h 5m works too.
- **Rounding:** every time is rounded to the nearest second, as a whole, so you will never see a pace like 5:60.
- **Distances:** the race buttons use World Athletics distances, 21.0975 km for the half marathon and 42.195 km for the marathon, and a mile is exactly 1.609344 km.

Finish times assume you hold the pace from start to finish. To plan a race kilometre by kilometre, or to run the second half faster, use the [split calculator](https://runpebble.me/split-calculator/).

## Sources

- Half marathon 21.0975 km and marathon 42.195 km: [World Athletics, Terms and Abbreviations](https://worldathletics.org/download/download?filename=WA_Terms__Abbreviations_EN+-+July+2023v2.pdf&urlslug=Terms+and+Abbreviations) (July 2023).
- 1 mile = 1.609 344 km and 1 mph = 1.609 344 km/h: [NIST Guide to the SI (Special Publication 811), Appendix B.8](https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8).

## More calculators for race day and every day

Predict it, split it, fuel it, log it.

- [Race time predictor](https://runpebble.me/race-time-predictor/): A recent race becomes predicted times from the mile to the marathon, with Riegel’s formula and its limits.
- [Split calculator & pace band](https://runpebble.me/split-calculator/): Even or negative splits per km or mile that add up exactly, and a wrist band to print.
- [Treadmill pace converter](https://runpebble.me/treadmill-pace-converter/): km/h and mph to pace per km and per mile, and back, with a table of common speeds.
- [Race fuel planner](https://runpebble.me/race-fuel-planner/): Carbohydrate per hour for your finish time, a gel or drink schedule, and a fluid check.
- [Running log](https://runpebble.me/running-log/): Runs saved on your device, weekly totals in km and miles, and CSV export and import.

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## Questions

**How do I work out my running pace?**

Divide your time by the distance. 55 minutes for 10 km is 5.5 minutes per kilometre, which is 5:30 per km. For pace per mile, multiply by 1.609344: 8:51 per mile.

**How long are a half marathon and a marathon?**

A half marathon is 21.0975 km (13.11 miles) and a marathon is 42.195 km (26.22 miles), the distances World Athletics uses. The race buttons above fill them in for you.

**What pace do I need for a two-hour half marathon?**

2:00:00 for 21.0975 km is 5:41 per km, or 9:09 per mile, at an even pace. The split calculator turns that into a split for every kilometre and a pace band you can print.

**What is the difference between pace and speed?**

Pace is time per distance, such as 5:30 per km; speed is distance per time, such as 10.91 km/h (6.78 mph). They describe the same running, upside down. Treadmills show speed, so the treadmill converter switches between the two.