Running Pace Calculator (Pace, Finish Time and Splits)
Pace per km and per mile from distance and time, or finish time from pace, for 5K, 10K, half and full marathon — with splits and Riegel race predictions.
Inputs
| Split | Elapsed |
|---|---|
| 1 km | 5:00 |
| 2 km | 10:00 |
| 3 km | 15:00 |
| 4 km | 20:00 |
| 5 km | 25:00 |
| Race | Riegel prediction | Same pace |
|---|---|---|
| 10K | 52:07 | 50:00 |
| Half marathon | 1:55:00 | 1:45:29 |
| Marathon | 3:59:47 | 3:30:59 |
- Distance
- 5 km
- Time
- 25:00
- Pace per km
- 5:00 /km
- Pace per mile
- 8:03 /mi
- Speed
- 12.00 km/h (7.46 mph)
- Working
- 25:00 ÷ 5 km = 5:00 /km
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- Two lines of HTML, unlimited views
- Shows a small CalculateEveryday bar, with a credit link under the calculator
What each Running Pace input means
- Work out
- Pace works out minutes per km or mile from a distance and a time. Finish time does the reverse, from a goal pace.
- Distance
- Pick a standard race to use its exact distance, or 'Enter a distance' for anything else — a training loop, a track session, a trail.
- Distance
- Kilometres, or miles when the units are set to imperial. GPS watches often read 1–2% long on a measured course.
- Minutes
- With hours and seconds, the total elapsed time. Minutes can go past 59 — 90 minutes is fine.
- Pace minutes (per km or mile)
- For finish times: the pace you plan to hold, per km in metric or per mile in imperial, with the seconds in the next box.
Running Pace formula
Pace = time ÷ distance · Finish time = pace × distance · Speed = distance ÷ time · Riegel: T₂ = T₁ × (D₂ ÷ D₁)^1.06
Pace is time per unit of distance — minutes per kilometre or per mile — and it is just the run's time divided by its distance. Run the other way, pace times distance gives a finish time, which is how runners plan a goal race. The page works in seconds throughout and shows both per-km and per-mile pace, the speed in km/h and mph, and even-pace splits for every kilometre or mile so you can check a watch mid-race. The race presets use the official road distances, so a marathon is 42.195 km (26.22 miles) and a half 21.0975 km, not a rounded 42 or 21. Under the splits, the page predicts times at the other standard distances two ways. 'Same pace' simply holds today's pace for longer, which nobody manages. Peter Riegel's formula, published in American Scientist in 1981 from world-record times, raises the distance ratio to the power 1.06 to allow for slowing as races get longer; it was fitted to efforts lasting roughly 3.5 to 230 minutes and is the basis of most race-time predictors.
Running Pace worked example
5 km in 25 minutes is 1,500 seconds ÷ 5 = 300 seconds a kilometre: a 5:00 /km pace, which is 8:03 a mile and 12.00 km/h. Riegel's formula predicts 1,500 × 2^1.06 = 3,127 seconds, or 52:07, for a 10K — about two minutes slower than holding the same pace — and 3:59:47 for a marathon.
More Running Pace examples
A half marathon at 9:30 a mile: 13.11 miles × 570 seconds is 7,472 seconds, a finish time of 2:04:32. The even-pace splits put mile 10 at 1:35:00.
To run a marathon in four hours: 14,400 seconds ÷ 42.195 km = 341 seconds, a pace of 5:41 /km or 9:09 a mile, and halfway should come at about 2:00:00.
Where the Running Pace calculator can give the wrong answer
- Pace is an average. A hilly course, a slow first kilometre or walk breaks all hide inside one number; the splits table assumes even pace throughout.
- Riegel's prediction assumes you have trained for the longer distance. From a 5K time, most runners without marathon training finish slower than the marathon prediction, and the exponent was fitted to elite records, not recreational runners.
- The formula was fitted to efforts of about 3.5 to 230 minutes. Predictions outside that — a sprint, or an ultra — are outside what it was built for.
- Seconds are rounded at the end, so a pace of 5:00.4 shows as 5:00. Over a marathon, rounding the pace before multiplying would drift by up to 20 seconds; the page multiplies first.
- For distances above 50 splits, the splits table is left out to keep the page readable; the pace and predictions still show.
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Running Pace reference table
| Race | Kilometres | Miles |
|---|---|---|
| 5K | 5 | 3.11 |
| 10K | 10 | 6.21 |
| Half marathon | 21.0975 | 13.11 |
| Marathon | 42.195 | 26.22 |
Running Pace FAQ
- Divide time by distance. 10 km in 55 minutes is 55 ÷ 10 = 5.5 minutes a kilometre, which is 5:30 /km. In miles, 3.1 miles in 27 minutes is 8.71 minutes, or 8:43 a mile.
- Multiply the per-km pace by 1.609. A 5:00 /km pace is 300 × 1.609 = 483 seconds, or 8:03 a mile; a 9:00 mile is 5:36 a kilometre. The page shows both for every result.
- A sub-2:00 half needs 5:41 per km or 9:09 per mile — the same paces as a 4-hour marathon, because a marathon is exactly twice the distance. A sub-30 5K needs 6:00 /km or 9:39 a mile.
- It is good between nearby distances — a 10K from a 5K, a half from a 10K — for runners trained for both. It tends to be optimistic for the marathon unless the training included long runs, because the 1.06 exponent came from record holders.
- There's no single 'good' — 6:00–7:00 /km (about 9:40–11:15 a mile) is common for new runners building endurance. Compare against your own past runs rather than elite benchmarks; the heart-rate-zones page helps keep easy runs easy.