Pace and speed
Runners usually think in pace: the minutes and seconds it takes to cover one mile (or kilometre), such as 9:00 per mile. Cyclists think in speed: miles or kilometres per hour. One is the inverse of the other:
pace (min/mile) = time / distance
>
speed (mph) = 60 / pace in minutes
A pace of 10:00 per mile is therefore 6 mph, and 8:00 per mile is 7.5 mph. Enter times as h:mm:ss (1:05:30) or mm:ss (28:30), and a pace as mm:ss (9:00).
Worked examples
- 5K (3.1 miles) in 28:30: your pace is 28.5 / 3.1 ≈ 9:12 per mile, about 6.5 mph or 5:43 per km.
- Marathon at 9:00 per mile: 26.2 × 9 minutes ≈ 3:55:48.
- Sub-4-hour marathon: 240 minutes / 26.2 miles = an average of 9:10 per mile (5:41 per km) or faster.
- Half marathon at 5:30 per km: 21.1 km × 5.5 minutes ≈ 1:56:02.
Race distances
The table below the result shows how long the standard distances take at the same pace:
- 5K and 10K: 3.1 and 6.2 miles, the most popular distances for recreational runners.
- Half marathon: 13.1 miles (21.0975 km).
- Marathon: 26.2 miles (42.195 km).
Keep in mind that most runners can't hold the same pace over a longer distance as over a short one. The table assumes an even pace; to predict a realistic marathon time from a 10K, allow a generous margin, especially if you haven't done many long runs yet.
Training by pace
Most training plans use several paces:
- Easy run: a conversational pace, often a minute or more per mile slower than race pace.
- Tempo run: a comfortably hard pace you could hold for about an hour.
- Intervals: short repeats faster than your 5K pace, with recovery in between.
If you prefer to train by heart rate, work out your zones with the heart rate zone calculator. Your pace also depends on wind, hills, heat, humidity and the surface; on a hot day or a trail you'll naturally be slower.
Splits and negative splits
A split is the time for part of the distance, such as each mile. Starting a race too fast often costs a lot of time at the end, so many runners aim for a negative split: running the second half slightly faster than the first. Use the calculator to set your goal pace per mile and follow it on your watch during the race.
Miles and kilometres
Switch to km if you follow a metric plan or race abroad. One mile is 1.609 km, so 8:00 per mile is about 4:58 per kilometre. The calculator always shows your pace in both units.
Treadmill running
On a treadmill the speed is usually set in mph or km/h. Use the result of the calculator to translate your target pace: 9:00 per mile is 6.7 mph, 10:00 per mile is 6.0 mph. Many runners set a 1% incline to mimic the effort of running outdoors.
Frequently asked questions
How do I calculate my pace per mile?
Divide your time by the distance. 30 minutes over 3 miles is 10 minutes per mile.
How do I convert pace to mph?
Divide 60 by your pace in minutes. 8:00 per mile is 60 / 8 = 7.5 mph; 10:30 per mile is 60 / 10.5 ≈ 5.7 mph.
What pace do I need for a sub-4-hour marathon?
An average of 9:10 per mile (5:41 per km) or faster, before allowing for crowded starts or running wide on corners.
What is a good 5K time?
It depends heavily on age, experience and training. For beginners, finishing a 5K is an achievement; compare yourself with your own previous times.
Why does my watch show a different distance?
GPS is less accurate among tall buildings and trees and can cut corners. On a track or a certified course, the distance is exact.
Can I use this for cycling?
Yes. Enter the distance and time; your speed is shown in the result.
Last reviewed: 2026-10-06. Results are estimates for information only.