Pace Calculator
Calculate your running pace per kilometer and per mile, and your speed in km/h and mph, from distance and finish time, with projected 5K to marathon times at that pace.
Last updated: October 2026
Your pace and speed
5:06 per km (8:12 per mile), 11.8 km/h (7.3 mph)
Formula below · 3 sources (NIST, worldathletics.org, runnersworld.com) · Updated Oct 2026
Compare with similar
About this calculator
Pace is time per unit of distance, the inverse of speed. The calculator divides your total time by the distance:
pace per km = (hours × 3600 + minutes × 60 + seconds) ÷ distance in km
and shows it as minutes:seconds. Pace per mile is the pace per km times 1.609344, because a mile is exactly 1.609344 km. Speed is 3600 ÷ pace in seconds per km, in km/h, divided by 1.609344 for mph.
The chart below the result holds your pace over the standard race distances (5K, 10K, half marathon at 21.0975 km and marathon at 42.195 km). That is an even-pace projection, not a race prediction: most runners slow down over longer distances, so use it as a pacing target, not a forecast.
The result is your average for the whole run. GPS watches often measure a little long or short, especially among trees and buildings, so a certified course or a track gives the most accurate pace.
How to use
Enter the distance in kilometers and your finish time in hours, minutes and seconds. For miles, multiply by 1.609 first: 3.1 miles is 5 km, 6.2 miles is 10 km, 13.1 miles is 21.1 km and 26.2 miles is 42.2 km. Example (the defaults): 5 km in 25:30 is 1,530 seconds. 1,530 ÷ 5 = 306 seconds, a pace of 5:06 per km. Per mile: 306 × 1.609344 = 492 seconds, or 8:12. Speed: 3600 ÷ 306 = 11.8 km/h (7.3 mph). A 3:30:00 marathon (42.195 km) works out to 4:59 per km, 8:01 per mile.
Frequently asked questions
How do I convert pace per km to pace per mile?
Multiply by 1.609344. A 5:00 per km pace is 300 × 1.609344 = 483 seconds, or 8:03 per mile. To go the other way, divide by 1.609344.
What is the difference between pace and speed?
Pace is time per distance (minutes per km or mile); speed is distance per time (km/h or mph). They are inverses: 6:00 per km is 10 km/h. Runners use pace because race goals and training plans are written that way.
What pace do I need for a goal time?
Divide the goal time by the distance. A 2-hour half marathon (21.0975 km) needs 7,200 ÷ 21.0975 = 341 seconds per km, or 5:41 per km (9:09 per mile). Enter the distance and goal time here to check.
Why does my watch show a different pace?
GPS distance can be off by a few percent in cities, forests or on twisty courses, and watches smooth pace over a short window. The average over a measured distance is the most reliable figure.
Related calculators
Sources & references
Think a result is wrong? Report a problem with this calculator.