What this calculator does
Pace is time per unit distance, minutes per kilometre or per mile, and it is the number most runners actually train by. Speed is its inverse, distance per unit time, and is more common in cycling and on treadmills. This calculator moves between both and projects race times at the pace you enter.
The race projections assume you hold the same pace throughout, which is realistic over shorter distances and optimistic over longer ones. Marathon pace is typically slower than 10 km pace for the same runner, so treat the longer projections as an upper bound rather than a prediction.
The formula
Pace is total time divided by distance; speed is distance divided by time. Race times multiply the pace by each standard race distance. Converting between kilometres and miles uses the factor 1.60934.
| Term | Meaning |
|---|---|
| Pace | Minutes and seconds per kilometre or mile. |
| Speed | Kilometres or miles per hour. |
| Half marathon | 21.0975 km. |
| Marathon | 42.195 km. |
The inputs explained
| Field | What to enter |
|---|---|
| Distance (km) | The distance covered, in kilometres. |
| Time: minutes | Minutes taken. |
| Time: seconds | Seconds, on top of the minutes. |
When to use it
Working out your training pace
Enter a recent run to find the pace you actually held. Most training plans prescribe paces relative to race pace, so knowing your current figure is the starting point.
Setting a race target
Work backwards: adjust the pace until the projected finish time matches your goal. That gives the per-kilometre figure to hold on the day.
Converting between kilometres and miles
The per-mile pace is shown alongside, which is useful for following training plans or race courses that use different units.
Checking whether a goal is realistic
If the required pace is far faster than anything you have sustained in training, the goal probably needs adjusting. Race day gives a small boost, not a transformation.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
Race times at different 10 km paces
Common finishing times over 10 kilometres and the paces they represent.
| 10 km time | Pace | Speed | Half marathon | Marathon |
|---|---|---|---|---|
| 40 min | 4:00 min/km | 15.00 km/h | 1:24:23 | 2:48:47 |
| 45 min | 4:30 min/km | 13.33 km/h | 1:34:56 | 3:09:53 |
| 50 min | 5:00 min/km | 12.00 km/h | 1:45:29 | 3:30:59 |
| 55 min | 5:30 min/km | 10.91 km/h | 1:56:02 | 3:52:04 |
| 60 min | 6:00 min/km | 10.00 km/h | 2:06:35 | 4:13:10 |
| 70 min | 7:00 min/km | 8.57 km/h | 2:27:41 | 4:55:22 |
How distance affects pace at a fixed time
Fifty minutes of running covering different distances.
| Distance | Pace | Speed | Pace per mile |
|---|---|---|---|
| 5 km | 10:00 min/km | 6.00 km/h | 16:06 min/mile |
| 7 km | 7:09 min/km | 8.40 km/h | 11:30 min/mile |
| 8 km | 6:15 min/km | 9.60 km/h | 10:04 min/mile |
| 10 km | 5:00 min/km | 12.00 km/h | 8:03 min/mile |
| 12 km | 4:10 min/km | 14.40 km/h | 6:42 min/mile |
| 15 km | 3:20 min/km | 18.00 km/h | 5:22 min/mile |
Questions
How do I convert pace between kilometres and miles?
Multiply your per-kilometre pace by 1.60934 to get per-mile pace. A 5:00/km pace is about 8:03 per mile.
Are the race projections realistic?
Only for distances close to the one you entered. They assume constant pace, which holds reasonably for 5 km and 10 km but overstates performance at half marathon and marathon distance, where fatigue accumulates.
What is a good running pace?
It depends entirely on experience, age and goals. Many recreational runners sit between 5:30 and 7:00 per kilometre for easy running. Comparing against your own previous times is far more useful than comparing against others.
Should I train at race pace?
Mostly not. Most endurance programmes place the bulk of running at an easy pace well below race pace, with a smaller proportion of faster work. Training hard every session is a common and counterproductive mistake.
How much slower is marathon pace than 10 km pace?
Typically 30 to 60 seconds per kilometre for recreational runners, less for elites. Race prediction models exist for this, but the reliable approach is building up to the distance in training.
For aerobic capacity testing, see the VO₂ max calculator. For training intensity, use heart rate zones.