Pace Calculator
Find your running pace, finish time or distance from any two, in min/mile or min/km, with speed and projected times for 5K, 10K, half marathon and marathon.
Pace Calculator: with the default inputs, result is 8:03 /mi.
Ignored when solving for distance.
Ignored when solving for time.
Ignored when solving for pace.
- Pace per mile
- 8:03 /mi
- Pace per km
- 5:00 /km
- Total time
- 25:00
- Distance
- 5 km
- Speed
- 7.46 mph
Assumptions
- Pace is assumed even across the whole distance; projections to longer races do not model fatigue.
- 1 mile = 1,609.344 m; half marathon = 21.0975 km; marathon = 42.195 km.
- Times are rounded to the nearest second.
| Distance | Time | km | miles |
|---|---|---|---|
| 1 km | 5:00 | 1 | 0.62 |
| 1 mile | 8:03 | 1.61 | 1 |
| 5K | 25:00 | 5 | 3.11 |
| 10K | 50:00 | 10 | 6.21 |
| 10 miles | 1:20:28 | 16.09 | 10 |
| Half marathon | 1:45:29 | 21.1 | 13.11 |
| Marathon | 3:30:59 | 42.2 | 26.22 |
Assumes an even pace. Real race pace slows with distance — roughly 6% per doubling (Riegel) — so longer projections are optimistic.
| Split | Per mile (cumulative) | Per km (cumulative) |
|---|---|---|
| 1 | 8:03 | 5:00 |
| 2 | 16:06 | 10:00 |
| 3 | 24:08 | 15:00 |
| 4 | 32:11 | 20:00 |
| 5 | 40:14 | 25:00 |
| 6 | 48:17 | 30:00 |
| 7 | 56:20 | 35:00 |
| 8 | 1:04:22 | 40:00 |
| 9 | 1:12:25 | 45:00 |
| 10 | 1:20:28 | 50:00 |
How this is worked out
The formula
Pace = time ÷ distance Time = pace × distance Distance = time ÷ pace Speed = distance ÷ time 1 mile = 1,609.344 m · half marathon = 21.0975 km · marathon = 42.195 km
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Solve for
- Choose one of 3 options.Pace (from distance and time) · Time (from distance and pace) · Distance (from time and pace)
- Distance
- Ignored when solving for distance.in km, mi, m, yd · from 0 to 5000 · defaults to 5
- Time — hours
- Ignored when solving for time.from 0 to 99 · whole numbers only · defaults to 0
- Minutes
- A number.from 0 to 59 · whole numbers only · defaults to 25
- Seconds
- A number.from 0 to 59 · whole numbers only · defaults to 0
- Pace — minutes
- Ignored when solving for pace.from 0 to 59 · whole numbers only · defaults to 8
- Seconds
- A number.from 0 to 59 · whole numbers only · defaults to 0
- Pace per
- Choose one of 2 options.mile · kilometer
What you get back
- Resultmain answer
- Pace per mile
- Pace per km
- Total time
- Distance
- Speed
What this assumes
- Pace is assumed even across the whole distance; projections to longer races do not model fatigue.
- 1 mile = 1,609.344 m; half marathon = 21.0975 km; marathon = 42.195 km.
- Times are rounded to the nearest second.
About this calculator
Pace is time per unit distance — the runner's native unit — and every training plan, race goal and treadmill setting is written in it. This calculator solves for whichever of pace, time and distance you're missing, converts between minutes per mile and per kilometre, and projects finish times for the standard race distances.
How to use it
Choose what to solve for. To find your pace, enter the distance and time; to predict a finish, enter distance and target pace; to see how far you'd cover in a given time, enter time and pace. Distance takes km, miles, metres or yards; pace can be per mile or per kilometre. Everything converts automatically, so a 5K in 25:00 shows as 8:03 per mile and 5:00 per kilometre.
Reading the results
- Pace per mile / per km are the two numbers you'll want side by side when a plan uses one and your watch the other.
- Speed in mph or km/h is what treadmills use. 8:00 per mile is 7.5 mph.
- The finish-time table applies your pace evenly across 1K to the marathon. Useful for setting targets, but be honest: nobody holds 5K pace for 42 km.
Even pace isn't realistic across distances
Race pace slows as distance grows. Riegel's formula, the basis of most race predictors, says time scales with distance to the power 1.06 — roughly 6% slower per mile every time the distance doubles. A 25:00 5K predicts about a 52:00 10K and a 4:00 marathon, not the 3:31 the even-pace table shows. Use the table for "what if I hold this pace," not "what will I run."
Pacing tips the numbers support
- Negative or even splits produce the best times. Most world records were run with the second half at or faster than the first.
- Course and conditions matter: add 10–20 seconds per mile for hills, heat above 20 °C, or a heavy trail surface.
- GPS distance is usually 0.5–2% long on a certified course because you can't run the tangents perfectly; your "pace" on race day will read slightly faster than the official result.
If you're planning splits, the split table lists cumulative times at each mile and kilometre so you can write them on your arm.
Frequently asked questions
▸How do I calculate running pace?
Divide total time by distance. 25 minutes for 5 km is 5:00 per km; divide by 3.107 miles instead and it's 8:03 per mile.
▸How do I convert min/mile to min/km?
Divide the pace in seconds by 1.609. 8:00 per mile (480 s) is 298 s, or 4:58 per km. Going the other way, multiply by 1.609.
▸What pace do I need for a 4-hour marathon?
9:09 per mile, or 5:41 per km, held evenly for 26.2 miles. Most runners aim to start 5–10 seconds per mile slower and finish strong.
▸What speed on the treadmill is 8 min/mile pace?
7.5 mph, or 12.1 km/h. Speed in mph is 60 divided by the pace in minutes per mile.
▸Can I use my 5K time to predict a marathon?
Roughly, with Riegel's formula: T2 = T1 × (D2 ÷ D1)^1.06. A 25:00 5K predicts around 4:00 for the marathon — much slower than holding 5K pace, which is what an even-pace table shows.
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