Pace Calculator
Pace is time divided by distance. 25:00 for 5K is a pace of 5:00 per km, or 8:03 per mile, a speed of 12.00 km/h = 7.46 mph. Choose what to solve for (pace, finish time or distance), enter the other two, and the calculator works it out exactly from seconds and metres, with cumulative kilometre and mile splits and finish times for the 400 m, mile, 5K, 10K, half marathon and marathon at that pace. It works the same for running, walking and cycling, and takes times as 25:00, 1:45:30, 45m or 1h 5m.
Updated Runs in your browser: nothing you enter is uploadedHow this tool works
Pace 5:00 per km
8:03 per mile · 12.00 km/h · 7.46 mph
- Distance
- 5 km = 3.107 miles
- Time
- 25:00
- Pace per km
- 5:00
- Pace per mile
- 8:03
- Speed
- 12.00 km/h = 7.46 mph
Times and paces are rounded to the nearest whole second, speeds to 2 decimals and distances to 3 decimals.
Even-pace splits
Cumulative time at each kilometre and mile, running the whole distance at this pace.
| Km | Time |
|---|---|
| 1 | 5:00 |
| 2 | 10:00 |
| 3 | 15:00 |
| 4 | 20:00 |
| 5 (finish) | 25:00 |
| Mile | Time |
|---|---|
| 1 | 8:03 |
| 2 | 16:06 |
| 3 | 24:08 |
| 3.107 (finish) | 25:00 |
Finish times for common races
“At this pace” holds the pace above for the whole race. The estimate uses the Riegel formula, T2 = T1 × (D2 ÷ D1)^1.06, on your time and distance: a rough guess that assumes similar conditions, not a prediction.
| Race | At this pace | Riegel estimate |
|---|---|---|
| 400 m | 2:00 | 1:43 |
| Mile | 8:03 | 7:31 |
| 5K | 25:00 | 25:00 |
| 10K | 50:00 | 52:07 |
| Half marathon | 1:45:29 | 1:55:00 |
| Marathon | 3:30:59 | 3:59:47 |
Finish times at common paces
| Pace per km | Pace per mile | Speed (km/h) | 5K | 10K | Half marathon | Marathon |
|---|---|---|---|---|---|---|
| 4:00 | 6:26 | 15.00 | 20:00 | 40:00 | 1:24:23 | 2:48:47 |
| 4:30 | 7:15 | 13.33 | 22:30 | 45:00 | 1:34:56 | 3:09:53 |
| 5:00 | 8:03 | 12.00 | 25:00 | 50:00 | 1:45:29 | 3:30:59 |
| 5:30 | 8:51 | 10.91 | 27:30 | 55:00 | 1:56:02 | 3:52:04 |
| 6:00 | 9:39 | 10.00 | 30:00 | 1:00:00 | 2:06:35 | 4:13:10 |
| 6:30 | 10:28 | 9.23 | 32:30 | 1:05:00 | 2:17:08 | 4:34:16 |
| 7:00 | 11:16 | 8.57 | 35:00 | 1:10:00 | 2:27:41 | 4:55:22 |
Common distances in kilometres and miles
| Distance | Kilometres | Miles |
|---|---|---|
| 400 m | 0.4 | 0.249 |
| Mile | 1.609344 | 1 |
| 5K | 5 | 3.107 |
| 10K | 10 | 6.214 |
| Half marathon | 21.0975 | 13.109 |
| Marathon | 42.195 | 26.219 |
How to calculate pace, finish time or distance
- Choose what to solve for. Pick pace, finish time or distance in “Solve for”. The two fields you need stay visible and the third is worked out.
- Enter the distance. Pick a preset (5K, 10K, half marathon, marathon, mile or 400 m) or choose a custom distance in kilometres or miles. A 5K is 5 km, which is 3.107 miles.
- Enter the time or the pace. Type a time as 25:00, 1:45:30, 45m or 1h 5m. A pace is typed the same way, as minutes and seconds per km or per mile: 5:30 per km is 5 minutes 30 seconds for every kilometre.
- Read the result. 25:00 over 5K gives 5:00 per km and 8:03 per mile. The same effort over a marathon at a steady 5:30 per km would finish in 3:52:04.
- Use the splits. The splits table gives the cumulative time at each kilometre and each mile for an even pace, and the race table gives finish times for the common distances at the same pace.
Frequently asked questions
- How do I calculate running pace?
- Divide the time by the distance. 25:00 (1,500 seconds) for 5 km is 1,500 ÷ 5 = 300 seconds per km, which is 5:00 per km. For a pace per mile, divide by the distance in miles instead: 1,500 ÷ 3.10686 = 8:03 per mile.
- How do I convert pace per km to pace per mile?
- Multiply the pace per km by 1.609344, because a mile is exactly 1.609344 km. A pace of 5:00 per km is 300 s × 1.609344 = 482.8 s, which rounds to 8:03 per mile. Going the other way, divide the pace per mile by 1.609344. The calculator shows both from the exact values, not from an already rounded pace.
- How do I find my finish time from my pace?
- Multiply the pace by the distance. At 5:30 per km a marathon (42.195 km) takes 3:52:04, and at 5:00 per km a half marathon (21.0975 km) takes 1:45:29. Choose “Finish time” in “Solve for”, then enter the distance and the pace.
- How do I find the distance from a time and a pace?
- Divide the time by the pace. In 1h 5m at 6:30 per km you cover 10 km = 6.214 miles. Choose “Distance” in “Solve for”, enter the time and the pace, and say whether the pace is per km or per mile.
- How do I convert pace to speed in km/h or mph?
- Speed is distance over time. A pace of 5:00 per km covers 1 km in 300 seconds, so 3,600 ÷ 300 = 12.00 km/h (7.46 mph). A pace of 8:00 per mile is 12.07 km/h = 7.50 mph. A slower pace is a lower speed: the two move in opposite directions.
- What time formats can I type?
- Minutes and seconds as 25:00, hours, minutes and seconds as 1:45:30 (seconds may have decimals), units as 45m, 1h 5m, 1h5m30s or 90s, or a plain number, which is minutes (5.5 means 5:30). In hours:minutes:seconds the minutes and seconds must be below 60, while 90:00 is read as 90 minutes.
- How are results rounded?
- The calculation is exact: times are whole milliseconds, distances are whole millimetres and the mile is exactly 1.609344 km. Only the shown results are rounded: paces, split times and finish times to the nearest whole second (halves round up), speeds to 2 decimals and distances to 3 decimals. Each split comes from the exact pace, so rounding never builds up from one split to the next.
- Does the pace calculator work for walking and cycling?
- Yes. Pace and speed are just time and distance, whatever the activity. Walking 3 miles in 1:00:00 is 20:00 per mile, 12:26 per km and 4.83 km/h = 3.00 mph. For cycling, speed in km/h or mph is usually the more familiar number and is shown beside the pace.
- What is the Riegel formula, and how reliable is the estimate?
- Riegel’s formula estimates a finish time at another distance from one effort: T2 = T1 × (D2 ÷ D1)^1.06, where T1 is your time over distance D1. From 25:00 for 5K it gives 3:59:47 for a marathon, while simply holding the 5K pace would give 3:30:59. It is a rough estimate from a published rule of thumb, not a prediction: it assumes similar conditions and a comparable level of effort, and it is less reliable the further the new distance is from the original one. The tool labels it an estimate.
- Are the splits for an even pace?
- Yes. The splits table assumes the whole distance is run at the one pace, with no faster or slower sections, and lists the cumulative time at each whole kilometre and each whole mile, then the finish. Real races rarely stay perfectly even, so treat the table as a reference rather than a plan.
- Is anything I type sent anywhere?
- No. The calculation runs in your browser and the times and distances you enter are not sent or stored. This page only does arithmetic: it gives no training, health or fitness advice.
How it works
Every result comes from one exact ratio of whole milliseconds to whole millimetres. A time is read into whole milliseconds and a distance into whole millimetres (1 km = 1,000,000 mm, 1 mile = 1,609,344 mm exactly, the half marathon 21,097,500 mm and the marathon 42,195,000 mm). The three solves are: pace = time ÷ distance, time = pace × distance, distance = time ÷ pace. Products and quotients are done with big integers, with no floating-point step. A pace per km is the effort’s milliseconds multiplied by 1,000,000 mm and divided by its millimetres; per mile it uses 1,609,344 mm. Speed in km/h is distance in km ÷ time in hours, and in mph it is distance in miles ÷ time in hours. Display rule: paces, split times and finish times are rounded to the nearest whole second with halves rounding up, speeds to 2 decimals and distances to 3 decimals with trailing zeros dropped. Splits use the exact effort at each whole kilometre or mile (k × 1 km or k × 1 mile) and then the finish at the exact distance, so no rounding accumulates between rows; they are listed for up to 250 km or miles. The finish-time table multiplies the exact pace by each race distance. The optional estimate uses Riegel’s formula, T2 = T1 × (D2 ÷ D1)^1.06, computed in floating point and rounded to a whole second; it is an estimate, not an exact result. Times accept m:ss, h:mm:ss, units such as 1h 5m, or a plain number of minutes; limits are 10,000 km and 1,000 hours. Everything runs in your browser.
Sources
- Pace, Wikipedia
- Mile, Wikipedia (1 mile = 1.609344 km)
- Marathon, Wikipedia (42.195 km)
- Peter Riegel, “Athletic Records and Human Endurance”, American Scientist, 1981
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