Pace is the time it takes to cover one kilometre or one mile: pace = time ÷ distance. Hold 5:30 per kilometre and you will finish a 10K in 55:00. Multiply your pace by the race distance to get a finish time, or divide your target time by the distance to find the pace you need.
Most people slow down over longer distances, so a pace you can hold for a 5K will usually be too fast for a marathon.
How pace, time and distance fit together
Pace, distance and finish time are linked by one simple relationship:
- Finish time = pace × distance
- Pace = finish time ÷ distance
Pace is quoted as minutes per kilometre or per mile. Speed is the same thing the other way around: 5:30 per kilometre is about 10.9 km/h. There are about 1.609 kilometres in a mile, so a pace per mile is roughly 1.609 times the pace per kilometre.
Common race distances
| Race | Distance |
|---|---|
| 5K | 5 km |
| 10K | 10 km |
| 10 miles | about 16.09 km |
| Half marathon | 21.0975 km |
| Marathon | 42.195 km |
Our Running pace and finish time tool has all of these built in, plus a custom distance box for anything else.
Worked examples
Finish time from pace. At a steady 5:30 per kilometre, the tool gives:
| Distance | Time at 5:30/km |
|---|---|
| 5K | 27:30 |
| 10K | 55:00 |
| Half marathon | 1:56:02 |
| Marathon | 3:52:04 |
That is also 8:51 per mile.
Pace from a target time. To run a half marathon in 1:55:00, you need about 5:27 per kilometre, or 8:46 per mile. A 5K in 25:00 needs exactly 5:00 per kilometre.
The marathon figure shown for each pace assumes you hold the same pace the whole way. In practice, tiredness, hills and weather usually make the later miles slower.
Predicting longer races with the Riegel formula
The Riegel formula is a well-known way to estimate a time at another distance from one recent result:
T2 = T1 × (D2 ÷ D1)^1.06
Here T1 is your known time at distance D1, and D2 is the new distance. The exponent of 1.06 builds in the usual slowdown over longer distances.
If you ran 10K in 50:00:
- Half marathon: 50:00 × (21.0975 ÷ 10)^1.06 is about 1:50:19
- Marathon: 50:00 × (42.195 ÷ 10)^1.06 is about 3:50:01
Compare that with the constant-pace figures: at 5:00 per kilometre you would get 1:45:29 for the half and 3:30:59 for the marathon. The Riegel estimate is more realistic, and still assumes you have trained for the longer distance. Treat it as a ceiling on what is realistic, not a promise.
Setting a realistic goal time
A good goal sits just beyond your current ability. Take a recent race or a hard, evenly paced time trial, run it through the Riegel formula for the new distance, then add a little margin if the course is hilly or the weather may be warm.
It also helps to think in splits. For a 10K target of 55:00, you would aim for 5:30 per kilometre, so you can check at each kilometre marker whether you are on track. A watch or phone app that shows lap pace makes this easy, but even a clock at the 5K point is useful.
Training and pacing tips
- Start a race slightly slower than target pace and speed up if you feel good.
- Build weekly mileage gradually, and include easy runs as well as harder sessions.
- Drink to suit the weather and distance. See How much water should you drink each day? for a guide to daily fluid needs.
- Sleep helps recovery. Sleep cycles: how to choose a bedtime or wake-up time explains how to plan a night before an early start.
- Longer training uses more energy; Calories and TDEE: how many calories do you need? explains how to estimate daily calories.
Note: This is general information, not medical or coaching advice. Our calculator gives estimates. If you are new to running, returning from injury or have a health condition, speak to a GP before building up distance.
Try the calculator
Use the Running pace and finish time calculator to turn a pace into a finish time, or a goal time into the pace you need, for any distance.
Open the free Running pace and finish time
Frequently asked questions
What is a good 5K time?
It depends on your age, fitness and experience. Finishing is a good first goal. After that, compare your own times over weeks and months.
How do I convert pace per kilometre to pace per mile?
Multiply by about 1.609. For example, 5:30 per kilometre is roughly 8:51 per mile.
Can I run a marathon at my 10K pace?
Almost never. Most runners slow down significantly over longer distances, which is why formulas such as Riegel’s add a slowdown factor.
How accurate are predicted race times?
They are estimates. Training, course, weather and pacing all matter, so treat predictions as a rough guide.