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
Pace chart: from 4:30 to 7:00 per kilometre
If you know your usual easy or race pace, this table shows what it means over the standard distances. Every figure comes from our running pace calculator, assuming the same pace from start to finish.
| Pace per km | Pace per mile | Speed | 5K | 10K | Half marathon | Marathon |
|---|---|---|---|---|---|---|
| 4:30 | 7:15 | 13.3 km/h | 22:30 | 45:00 | 1:34:56 | 3:09:53 |
| 5:00 | 8:03 | 12 km/h | 25:00 | 50:00 | 1:45:29 | 3:30:59 |
| 5:30 | 8:51 | 10.9 km/h | 27:30 | 55:00 | 1:56:02 | 3:52:04 |
| 6:00 | 9:39 | 10 km/h | 30:00 | 1:00:00 | 2:06:35 | 4:13:10 |
| 6:30 | 10:28 | 9.2 km/h | 32:30 | 1:05:00 | 2:17:08 | 4:34:16 |
| 7:00 | 11:16 | 8.6 km/h | 35:00 | 1:10:00 | 2:27:41 | 4:55:22 |
Notice that every extra 30 seconds per kilometre adds about 2 minutes 30 seconds to a 5K but nearly 21 minutes to a marathon. Small differences in pace matter far more as the distance grows, which is why pacing discipline is the main skill in longer races.
Worked example 2: predicting from a 5K and from a half marathon
The Riegel formula (T2 = T1 × (D2 ÷ D1)^1.06) works from any distance, not just 10K. Here are two more starting points, calculated by us and checked independently.
| Recent result | Predicted 10K | Predicted half marathon | Predicted marathon |
|---|---|---|---|
| 5K in 25:00 | 52:07 | 1:55:00 | 3:59:47 |
| 10K in 50:00 | (your result) | 1:50:19 | 3:50:01 |
| Half marathon in 1:45:00 | 43:03 (for 10K) | (your result) | 3:18:04 |
Two things stand out. First, a 25:00 5K is exactly 5:00 per kilometre, yet the predicted 10K is 52:07, about 5:13 per kilometre. The formula assumes you will slow slightly as the distance doubles. Second, predictions from a short race to a marathon are the least reliable. A 5K tells you about speed, but a marathon is mostly decided by endurance, long runs and fuelling. If you can, use a result from a distance close to your target, such as a half marathon when planning a marathon.
Step by step: working it out by hand
You do not need a calculator to check a pace, only seconds.
- Convert your target time to seconds. A 55:00 10K is 55 × 60 = 3,300 seconds.
- Divide by the distance in kilometres: 3,300 ÷ 10 = 330 seconds per kilometre.
- Convert back: 330 seconds is 5 minutes 30 seconds, so 5:30 per kilometre.
- For pace per mile, multiply the seconds by 1.609: 330 × 1.609 is about 531 seconds, or 8:51.
- For speed in km/h, divide 3,600 by the seconds per kilometre: 3,600 ÷ 330 is about 10.9 km/h.
For a half marathon in 1:55:00 (6,900 seconds), divide by 21.0975 to get about 327 seconds, or roughly 5:27 per kilometre.
Pacing strategies for race day
- Even pace. Holding the same pace throughout is efficient and easy to monitor. It suits flat courses and runners who know their limit.
- Negative split. Running the second half slightly faster than the first. It feels controlled and avoids the common problem of starting too fast, but it takes discipline in the first few kilometres when you feel fresh.
- Effort-based pacing. On hilly or windy courses, a fixed pace is unrealistic. Run by feel or heart rate, and expect uphill kilometres to be slower and downhill ones faster. Our Heart rate zones explained: how to find your maximum and train by zone guide explains how effort zones work.
- Walk breaks. Planned walking at aid stations or at set intervals is a legitimate strategy, particularly in a first marathon. Include the breaks in your average pace when you set a goal.
Whatever the plan, write your target splits on your wrist or phone before the start. Race-day adrenaline makes the first kilometre feel easier than it is.
Common mistakes with pace and goal times
- Setting a goal from your best day. Use a recent, honestly paced result, not a one-off personal best from years ago.
- Treating the constant-pace marathon figure as a target. It is the time you would get if you did not slow down at all, which almost nobody does.
- Mixing kilometres and miles. A pace of 8:00 per mile is much faster than 8:00 per kilometre. Check the unit on your watch and on the race course markers.
- Ignoring conditions. Heat, wind, hills and crowded starts all cost time. Many runners add a few minutes to a marathon prediction for a warm day.
- Forgetting recovery and fuelling. Long runs and races use a lot of energy. See Calories and TDEE: how many calories do you need? for how to estimate what you burn and eat.
Glossary
- Pace: time taken per unit of distance, such as minutes per kilometre.
- Split: the time for one section of a race, such as a kilometre or mile.
- Negative split: a second half faster than the first.
- Time trial: a hard, evenly paced effort over a known distance, used to measure fitness.
- Taper: reducing training in the last one to three weeks before a race so you arrive fresh.
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.
What is the difference between pace and speed?
They describe the same thing in opposite ways. Pace is time per distance (5:30 per kilometre), while speed is distance per time (about 10.9 km/h). Treadmills usually show speed and watches show pace.
How do I work out the pace for a half marathon in under two hours?
Two hours is 7,200 seconds. Divide by 21.0975 and you get about 341 seconds, or roughly 5:41 per kilometre (about 9:09 per mile). Aim slightly faster to leave a small margin.
Should I use the Riegel formula for very short or very long races?
It works best between about 5K and the marathon. For much shorter or ultra-length events, other factors dominate, so treat any prediction with extra caution.
Does running on a treadmill change my pace?
Often a little. Treadmill speed is steady and has no wind, so many runners find the same effort gives a slightly different pace outdoors. Compare like with like when setting goals.