How to use this calculator
- Enter or choose distance.
- Enter or choose pace per.
- Add a grade and credits for each course; leave unused rows blank.
- The result updates as you type. Use Copy result or Share to keep it.
Method
Pace = Time ÷ Distance; Time = Pace × Distance; Distance = Time ÷ Pace; Speed (km/h) = 60 ÷ pace (min/km)
- 1 mile
- 1.609344 km (exact)
- half marathon
- 21.0975 km
- marathon
- 42.195 km
Worked example
- 50 minutes = 3,000 seconds; 3,000 ÷ 10 km = 300 s = 5:00 per km.
- Per mile: 300 × 1.609344 = 482.8 s ≈ 8:03 per mile.
- Speed = 60 ÷ 5 = 12 km/h = 12 ÷ 1.609344 = 7.46 mph.
Running 10 km in 50 minutes is a pace of 5:00 per km (8:03 per mile), or 12 km/h.
What the result means
The finish-time table assumes you can hold the same pace for longer distances, which few runners can. As a rough guide, expect your pace to slow as the distance increases, especially beyond the half marathon.
Assumptions and limits
- Even pace throughout.
- Paces and times are rounded to the nearest second.
- Does not adjust for hills, heat, wind or fatigue.
- GPS distance can differ from the officially measured course, so watch pace and official pace may not match exactly.
Questions
What pace is a sub-4-hour marathon?
Just under 5:41 per km (9:09 per mile): 42.195 km at 5:41 per km takes 3:59:48.
How do I convert pace per km to pace per mile?
Multiply the pace in seconds by 1.609344. For example, 5:00 per km is 300 s × 1.609344 = 483 s, or 8:03 per mile.