What does pace mean in running?
Runners rarely talk about kilometres per hour. What counts among runners is pace: the time it takes you to cover one kilometre. A pace of 5:30 means 5 minutes and 30 seconds per kilometre. The lower the number, the faster you are going.
The reason for this is practical. In training and racing you think in kilometres: at every kilometre marker you know immediately whether you are on schedule. Pace also gives you your finish time directly, because you only need to multiply by the distance. That is much harder with km/h. This guide shows you the formulas, typical values and how to pace a race wisely. You can work out your own values in the pace calculator.
How to calculate your pace
The basic formula is: pace = time ÷ distance. If you run 10 km in 50 minutes, that is 50 ÷ 10 = 5 minutes per kilometre. Your pace is 5:00 min/km.
It gets trickier with odd times, because minutes and seconds do not count in tens. The safest way is to convert everything to seconds:
1. Convert the time to seconds: 52:30 minutes are 52 × 60 + 30 = 3,150 seconds.
2. Divide by the distance: 3,150 ÷ 10 km = 315 seconds per kilometre.
3. Convert back to minutes and seconds: 315 seconds are 5 minutes and 15 seconds, so 5:15 min/km.
The most common mistake is reading 52:30 as 52.3 minutes. The correct value is 52.5 minutes, because 30 seconds are half a minute. Even this small error shifts the result by several seconds per kilometre.
Rearranging the formula
If you know two of the three values, you can always get the third:
1. Time = distance × pace. A half marathon (21.0975 km) at 5:00 min/km takes 21.0975 × 300 seconds = 6,329 seconds, or about 1:45:29.
2. Distance = time ÷ pace. In one hour at 6:00 min/km you cover 3,600 ÷ 360 = 10 km.
That is exactly how the pace calculator works: choose which value you are looking for at the top and enter the other two.
Converting pace to km/h and back
Treadmills usually show speed in km/h, while training plans use min/km. The conversion is easy once you write the pace as a decimal:
1. km/h = 60 ÷ pace in minutes. 5:00 min/km gives 60 ÷ 5 = 12 km/h.
2. Pace in minutes = 60 ÷ km/h. 10 km/h gives 60 ÷ 10 = 6 minutes, so 6:00 min/km.
Again, 5:30 min/km is 5.5 minutes, which equals 10.9 km/h. A quick overview:
| Pace (min/km) | km/h | min/mile | 10K | Half marathon | Marathon |
|---|---|---|---|---|---|
| 4:00 | 15.0 | 6:26 | 0:40:00 | 1:24:23 | 2:48:46 |
| 4:30 | 13.3 | 7:15 | 0:45:00 | 1:34:56 | 3:09:52 |
| 5:00 | 12.0 | 8:03 | 0:50:00 | 1:45:29 | 3:30:58 |
| 5:30 | 10.9 | 8:51 | 0:55:00 | 1:56:02 | 3:52:04 |
| 6:00 | 10.0 | 9:39 | 1:00:00 | 2:06:35 | 4:13:10 |
| 6:30 | 9.2 | 10:28 | 1:05:00 | 2:17:08 | 4:34:16 |
| 7:00 | 8.6 | 11:16 | 1:10:00 | 2:27:40 | 4:55:21 |
You mainly need the mile pace for training plans from the US or UK. One mile is 1.609344 km, so multiply the kilometre pace by that factor. A detailed treadmill conversion table is in the article Converting km/h to min/km.
Which pace do you need for your target time?
Most runners go the other way: they have a target time in mind and want to know how fast they need to run. The official distances are 5K, 10K, the half marathon at 21.0975 km and the marathon at 42.195 km. The key thresholds at a glance:
| Goal | Required pace | km/h |
|---|---|---|
| 5K under 25:00 | 5:00 min/km | 12.0 |
| 5K under 30:00 | 6:00 min/km | 10.0 |
| 10K under 50:00 | 5:00 min/km | 12.0 |
| 10K under 1:00:00 | 6:00 min/km | 10.0 |
| Half marathon under 1:45:00 | 4:59 min/km | 12.1 |
| Half marathon under 2:00:00 | 5:41 min/km | 10.5 |
| Marathon under 3:30:00 | 4:59 min/km | 12.1 |
| Marathon under 4:00:00 | 5:41 min/km | 10.5 |
Allow a few seconds per kilometre of buffer. In big city races you rarely run the ideal line, and at the finish your watch often shows 200 to 400 metres more than the official distance. If you run exactly 5:41 min/km, you can easily miss the 4-hour marathon.
Even pace or negative split?
The biggest trap in a race is the start. Your legs are fresh, the atmosphere is great and the first kilometres feel easy. If you run 10 to 15 seconds per kilometre too fast here, you often pay it back twice in the second half.
Many coaches therefore recommend an even pace or a negative split: the second half slightly faster than the first. A small difference is enough. In a 1:45:00 half marathon with a 2% negative split you run the first half in about 53:02 and the second in about 51:58. That is a difference of around 6 seconds per kilometre.
In the pace calculator you set the negative split with a slider. The split table then shows your elapsed time at every kilometre. Print it out or write down the times for every 5 km, so you notice straight away if you are going too fast. How big the difference should be is explained in Negative Split: How to Pace Your Race.
What to watch on race day
1. Heat: from about 20 degrees Celsius most runners slow down. On warm days, plan a slightly slower pace on purpose and drink in good time. How much fluid you need day to day is shown by the water intake calculator.
2. Hills: you lose time uphill and only win part of it back downhill. On hilly courses it is better to run by feel than to stick rigidly to a pace.
3. Crowds: in big races the first kilometre is often slower. Do not try to make up the lost seconds immediately; spread them over the race.
Pace in training: not every run is a race
A common mistake is running every training session at the same pace. Most kilometres should be easy, clearly slower than your race pace. Rules of thumb, each relative to your 10K race pace:
1. Recovery: about 30 to 40% slower, very easy.
2. Easy / base runs: about 18 to 30% slower. You can hold a conversation.
3. Threshold / tempo run: about 3 to 7% slower, comfortably hard but controlled.
4. Intervals: about 2 to 6% faster, only in short repeats with recovery.
An example: if you run 10 km in 50:00 (5:00 min/km), easy runs fall roughly between 5:54 and 6:30 min/km. The pace calculator shows these ranges for your own time; more in How Fast Should You Run in Training? Please treat them as a rough guide. They do not replace a performance test or medical advice. If you have health issues or are returning after a long break, talk to your doctor first.
Running regularly also burns more energy. The calorie calculator shows how many calories you need on training days.
Estimating your finish time: the Riegel formula
How fast could you run a half marathon if you know your 10K time? That is what US engineer Peter Riegel's formula is for: T₂ = T₁ × (D₂ ÷ D₁)^1.06. From 50:00 over 10 km it predicts about 1:50:19 for the half marathon and 3:50:00 for the marathon.
The formula is an estimate. It assumes you are equally well trained for the longer distance. For the marathon in particular that is often not the case, and the prediction then turns out too optimistic. When the formula fits and where its limits lie is covered in Predicting Your Marathon Time.
Conclusion
Pace is the most important tool for pacing a race. With the formula time ÷ distance you can work it out quickly, as long as you convert the seconds properly. For your target time you need a realistic pace, a few seconds of buffer and ideally an even or slightly negative split. The pace calculator does the rest: it converts between pace, time and distance, builds your split table and estimates your finish times from 5K to marathon.