Pace Calculator
- Updated
- Formula shown
- Free, no sign-up
Results
10K in 55:00 is 5:30 per km or 8:51 per mile.
| Kilometer | Elapsed time | Miles |
|---|---|---|
| 1 | 5:30 | 0.62 |
| 2 | 11:00 | 1.24 |
| 3 | 16:30 | 1.86 |
| 4 | 22:00 | 2.49 |
| 5 | 27:30 | 3.11 |
| 6 | 33:00 | 3.73 |
| 7 | 38:30 | 4.35 |
| 8 | 44:00 | 4.97 |
| 9 | 49:30 | 5.59 |
| 10 | 55:00 | 6.21 |
Paces, speeds and predictions are estimates for planning training, not medical advice. If you are new to running or have a health condition, talk to a doctor before starting hard training.
How to use the pace calculator
- Choose what to work out: pace, finish time, distance, or a race-time prediction.
- Pick a race (1 mile, 5K, 10K, half marathon or marathon) or choose "Other distance" and enter it in kilometers, miles or meters.
- Enter the time in hours, minutes and seconds, or the pace in minutes and seconds per kilometer or per mile.
- Read the pace in both units, the speed and the splits. In prediction mode, enter a recent race and the race you are training for.
Pace formulas
time = pace × distance
distance = time ÷ pace
speed (km/h) = 60 ÷ pace (minutes per km)
pace per mile = pace per km × 1.609344
Riegel: T₂ = T₁ × (D₂ ÷ D₁)^1.06
Pace is the time it takes to cover one unit of distance, so it is simply the finish time divided by the distance. Speed is the same thing turned upside down. One mile is exactly 1.609344 km, which converts a pace per kilometer into a pace per mile. The race predictor uses Peter Riegel's endurance formula, where T₁ is your time over distance D₁ and T₂ is the predicted time over D₂. The exponent 1.06 makes each extra kilometer slightly slower than the last; it is a rule of thumb, so you can change it.
Worked example
A 10K run in 55:00 is 3,300 seconds ÷ 10 km = 330 seconds per kilometer, a pace of 5:30 per km. Multiply by 1.609344 and the pace is 8:51 per mile. The speed is 60 ÷ 5.5 = 10.91 km/h, or 6.78 mph.
For a prediction, take a 5K in 25:00. Riegel's formula gives 1,500 × 2^1.06 ≈ 3,127 seconds for a 10K, or 52:07: 2:07 slower than simply doubling the 5K time.
Finish times at common paces
| Pace per km | Pace per mile | 5K | 10K | Half marathon | Marathon |
|---|---|---|---|---|---|
| 4:00 | 6:26 | 20:00 | 40:00 | 1:24:23 | 2:48:47 |
| 4:30 | 7:15 | 22:30 | 45:00 | 1:34:56 | 3:09:53 |
| 5:00 | 8:03 | 25:00 | 50:00 | 1:45:29 | 3:30:59 |
| 5:30 | 8:51 | 27:30 | 55:00 | 1:56:02 | 3:52:04 |
| 6:00 | 9:39 | 30:00 | 1:00:00 | 2:06:35 | 4:13:10 |
| 6:30 | 10:28 | 32:30 | 1:05:00 | 2:17:08 | 4:34:16 |
| 7:00 | 11:16 | 35:00 | 1:10:00 | 2:27:41 | 4:55:22 |
Equivalent times from a 25-minute 5K
These Riegel estimates show how a single result translates to other distances, assuming you have trained for each one.
| Race | Predicted time | Pace per km |
|---|---|---|
| 1 mile | 7:31 | 4:40 |
| 5K | 25:00 | 5:00 |
| 10K | 52:07 | 5:13 |
| Half marathon | 1:55:00 | 5:27 |
| Marathon | 3:59:47 | 5:41 |
Tips for using pace
- Treat predictions as a starting point. They work best between nearby distances. A marathon predicted from a 5K assumes long runs in your training; without them, plan to start slower.
- Even or negative splits. Running the second half as fast as or slightly faster than the first usually beats going out hard. Use the split table as a checkpoint list.
- GPS distances drift. Watches often read a little long or short, especially among tall buildings and trees, while race courses are measured along the shortest legal line. Expect your watch pace to differ slightly from your official result.
- Hills, heat and wind count. The same effort gives a slower pace on a hot or hilly day, so judge hard sessions by effort or heart rate as well as by pace. The target heart rate calculator gives heart-rate zones.
Pace is a training guide, not a health measure. This is not medical advice; talk to a doctor or registered dietitian before starting a new training plan if you have a health condition. For strength work, see the one-rep max calculator.
Sources
- Riegel PS, "Athletic records and human endurance", American Scientist 1981;69(3):285–290.
- International mile: 1 mile = 1.609344 km exactly (international yard and pound agreement, 1959).
Frequently asked questions
How do I calculate my running pace?
Divide your time by the distance. A 10K in 55 minutes is 3,300 seconds ÷ 10 km = 330 seconds, or 5:30 per kilometer. Multiply by 1.609344 for the pace per mile: 8:51.
What pace do I need for a sub-4-hour marathon?
A marathon is 42.195 km (26.2 miles), so 4 hours needs an average of 5:41 per kilometer or 9:09 per mile. Running exactly 9:09 per mile finishes in 3:59:54, so there is very little margin; many runners aim slightly faster.
How do I convert pace per kilometer to pace per mile?
Multiply the pace per kilometer by 1.609344, because one mile is 1.609344 km. For example, 5:00 per km is 300 × 1.609344 = 483 seconds, or 8:03 per mile. To go the other way, divide by 1.609344.
How does the race-time predictor work?
It uses Peter Riegel’s formula, T₂ = T₁ × (D₂ ÷ D₁)^1.06. From a 25:00 5K it predicts about 52:07 for a 10K. It is a rule of thumb that assumes you have trained for the longer distance, so treat it as an estimate.
What is the difference between pace and speed?
Pace is time per distance (minutes per kilometer or mile); speed is distance per time (km/h or mph). They are reciprocals: a 5:00 per km pace is 60 ÷ 5 = 12 km/h, which is about 7.46 mph.