🏃 Pace Calculator
Convert a distance and time into pace and speed, or work out your finish time from a target pace.
Quick answer: Pace = time ÷ distance. Running 10 km in 50:00 is a pace of 5:00 per km, or 8:03 per mile – a speed of 12 km/h (7.46 mph).
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Pace Calculator inputs
Result
Your pace
5:00 /km
8:03 per mile over 10K
| Distance | 10 km · 6.214 mi |
| Time | 50:00 |
- Pace per km
- 5:00
- Pace per mile
- 8:03
- Speed
- 12 km/h · 7.46 mph
Race times at this pace
| Race | Finish time |
|---|---|
| 5K | 25:00 |
| 10K | 50:00 |
| Half marathon | 1:45:29 |
| Marathon | 3:30:59 |
How pace is calculated
Pace is the time taken to cover one unit of distance; speed is its inverse. Both are easy to convert between kilometres and miles using 1 mile = 1.609344 km.
Pace = total time ÷ distance · Time = pace × distance · Speed = distance ÷ time
Pace per mile = pace per km × 1.609344
Worked example
A 10K finished in 50:00: 3,000 seconds ÷ 10 km = 300 s = 5:00 per km. Multiplying by 1.609344 gives 482.8 s = 8:03 per mile. Speed is 10 ÷ (50/60) = 12 km/h, or 7.46 mph. Held for a full marathon, the same pace finishes in 3:30:59.
Common race distances
| Race | Kilometres | Miles |
|---|---|---|
| 5K | 5 | 3.11 |
| 10K | 10 | 6.21 |
| Half marathon | 21.0975 | 13.11 |
| Marathon | 42.195 | 26.22 |
Pacing tips
- Run the first few kilometres slightly slower than goal pace – fast starts cost more time later.
- Aim for even or slightly negative splits (second half faster).
- Use a recent race result to set realistic goal paces for longer distances.
- GPS watches often measure a little long; aim a few seconds per km faster than your target.
Predicting race times
Pace slows as distance increases, so a 10K pace cannot be held for a full marathon. A common rule of thumb (Riegel’s formula) predicts a longer race time as T2 = T1 × (D2 ÷ D1)1.06. A 50-minute 10K therefore suggests roughly 1:50 for a half marathon and 3:50 for a marathon – assuming you have done the training for that distance.
For general information only – not medical advice. Consult a healthcare professional.
Frequently asked questions
How do I convert pace per km to pace per mile?
Multiply the pace in seconds per km by 1.609344. For example 5:00/km = 300 s × 1.609 = 483 s = 8:03 per mile.
What is a good 5K pace?
It depends on age and experience. Many recreational runners finish a 5K in 25–35 minutes (5:00–7:00 per km). Beginners often start around 7:00–8:00 per km with walking breaks.
What pace do I need for a sub-4-hour marathon?
About 5:41 per km or 9:09 per mile, held for 42.195 km. Most runners aim slightly faster to allow for water stations and the final miles.
How do I convert pace to speed?
Divide 60 by the pace in minutes. A 5:00/km pace is 60 ÷ 5 = 12 km/h; an 8:00/mile pace is 7.5 mph.