Running pace is the time it takes you to cover one unit of distance, usually written as minutes per mile or minutes per kilometer. To find it, divide your total time by the distance. A 5K run in 25:00 works out to 25 ÷ 5 = 5:00 per km, which equals 8:03 per mile or 12 km/h.
Pace is the number runners live by. It tells you whether an easy run is actually easy, what finish time you can realistically aim for, and how to split a race so you do not fade in the last mile. Our running pace calculator turns any race result into pace per mile and per kilometer and predicts your next race. This guide explains the math behind it, from simple conversions to race prediction and training zones, using the same 25-minute 5K runner throughout so you can see how the numbers connect.
Pace vs speed: two ways to say the same thing
Speed and pace describe the same effort from opposite directions.
- Speed is distance per time: 12 km/h, 7.5 mph. Cyclists, drivers and treadmills use it.
- Pace is time per distance: 5:00 per km, 8:03 per mile. Runners use it because race distances are fixed and what you want to know is how long each mile or kilometer will take.
They are reciprocals. To convert speed to pace, divide 60 by the speed: 60 ÷ 12 km/h = 5 minutes per km. To go from pace to speed, divide 60 by the pace in decimal minutes: 60 ÷ 8.05 = 7.45 mph. Be careful with decimals: 8:03 per mile is 8.05 minutes, not 8.03. Seconds are sixtieths, not hundredths, and that slip causes more pace errors than anything else.
How to calculate your running pace
Pace = total time ÷ distance
- Convert your finish time to a single unit, usually seconds or decimal minutes. 52:07 becomes 52 × 60 + 7 = 3,127 seconds.
- Divide by the distance. 3,127 ÷ 10 km = 312.7 seconds per km.
- Convert back to minutes and seconds. 312.7 seconds is 5 minutes and 12.7 seconds, so about 5:13 per km.
The same formula rearranges to find time (pace × distance) or distance (time ÷ pace). The general pace calculator solves for whichever of the three you are missing, and it works for walking, cycling and swimming too.
Converting min/km to min/mile
A mile is exactly 1.609344 km. So:
- Pace per mile = pace per km × 1.609344
- Pace per km = pace per mile ÷ 1.609344
Do the multiplication in seconds. 5:00 per km is 300 seconds; 300 × 1.609344 = 482.8 seconds, which is 8:03 per mile. A quick mental version: add 60% to your per-km pace. That gets you within a few seconds.
| Pace per km | Pace per mile | Speed (km/h) | Speed (mph) | 5K time | 10K time |
|---|---|---|---|---|---|
| 4:00 | 6:26 | 15.0 | 9.3 | 20:00 | 40:00 |
| 4:30 | 7:15 | 13.3 | 8.3 | 22:30 | 45:00 |
| 5:00 | 8:03 | 12.0 | 7.5 | 25:00 | 50:00 |
| 5:30 | 8:51 | 10.9 | 6.8 | 27:30 | 55:00 |
| 6:00 | 9:39 | 10.0 | 6.2 | 30:00 | 1:00:00 |
| 6:30 | 10:28 | 9.2 | 5.7 | 32:30 | 1:05:00 |
| 7:00 | 11:16 | 8.6 | 5.3 | 35:00 | 1:10:00 |
For conversions between any speed units, including m/s and knots, the speed converter covers them all.
Splits: pacing a race evenly
A split is your time for one segment of a run, such as each mile, each kilometer or each lap. Splits show whether you held your pace or burned out early. To pace a goal, divide the goal time by the number of segments:
- A 4:00:00 marathon needs 5:41 per km or 9:09 per mile, which is 28:26 for every 5 km and exactly 2:00:00 at halfway.
- On a 400 m track, a 5:00 per km pace is a 2:00 lap.
Most coaches recommend even or slightly negative splits, meaning the second half is the same or a little faster than the first. Going out 10 seconds per km too fast in a marathon feels effortless for 25 km and then costs you minutes at the end. A sensible negative-split plan for a four-hour marathon might be 2:01:00 for the first half and 1:59:00 for the second. The running splits calculator lays out every kilometer or mile split for your target, and the marathon pace calculator does the same for the full 42.195 km.
Predicting race times with Riegel’s formula
In 1977 engineer and marathoner Pete Riegel noticed that race times across distances follow a simple power law:
T₂ = T₁ × (D₂ ÷ D₁)^1.06
T₁ and D₁ are a recent race time and distance; D₂ is the distance you want to predict. The exponent 1.06 is a little more than 1 because you inevitably slow down as distance grows. Here is what a 25:00 5K predicts:
| Race | Distance | Predicted time | Pace per km | Pace per mile |
|---|---|---|---|---|
| 5K (actual) | 5 km | 25:00 | 5:00 | 8:03 |
| 10K | 10 km | 52:07 | 5:13 | 8:23 |
| Half marathon | 21.0975 km | 1:55:00 | 5:27 | 8:46 |
| Marathon | 42.195 km | 3:59:47 | 5:41 | 9:09 |
Treat the marathon figure with care. Riegel’s formula assumes you have trained properly for the longer distance, and it tends to be optimistic for runners doing less than about 50 km a week, where an exponent of 1.07–1.08 fits better. Predictions from a recent 10K or half marathon are more reliable for a marathon than predictions from a 5K. The race time predictor lets you adjust the exponent and see predictions for every standard distance. Official race distances, by the way, are set by World Athletics, and certified road courses are measured to be at least the stated length.
Training paces: not every run should be race pace
Running every session at the same moderate pace is the most common training mistake. Different paces train different systems. Using the multipliers in our training pace calculator (based on your 10K-equivalent pace, here 5:13 per km), the 25-minute 5K runner gets:
| Run type | Purpose | Pace per km | Pace per mile |
|---|---|---|---|
| Easy | Aerobic base, recovery | 6:20 | 10:12 |
| Long run | Endurance, fat use | 7:08 | 11:29 |
| Tempo | Lactate threshold | 5:18 | 8:31 |
| Intervals | VO₂ max | 4:47 | 7:42 |
| Speed / reps | Running economy | 4:25 | 7:06 |
Notice how slow the easy pace is: well over a minute per km slower than 5K pace. That is deliberate. Most runners improve fastest when around 80% of their weekly running is genuinely easy, an approach explained in our guide to heart rate zones. If pace and heart rate disagree on a hot or hilly day, trust heart rate and effort. For a single number that summarizes fitness, the VO₂ max calculator for runners estimates Daniels’ VDOT from the same race result.
Treadmill pace conversions
Treadmills display speed, not pace, and US machines usually show mph. Use the table below, or divide 60 by the mph figure for minutes per mile.
| Treadmill (mph) | Pace per mile | km/h | Pace per km |
|---|---|---|---|
| 5.0 | 12:00 | 8.0 | 7:27 |
| 6.0 | 10:00 | 9.7 | 6:13 |
| 6.5 | 9:14 | 10.5 | 5:44 |
| 7.0 | 8:34 | 11.3 | 5:20 |
| 7.5 | 8:00 | 12.1 | 4:58 |
| 8.0 | 7:30 | 12.9 | 4:40 |
| 9.0 | 6:40 | 14.5 | 4:09 |
| 10.0 | 6:00 | 16.1 | 3:44 |
Running on a treadmill is slightly easier than running outside at the same speed because there is no air resistance and the belt helps a little with leg turnover. A frequently cited 1996 study by Jones and Doust found that a 1% incline makes treadmill running roughly match the energy cost of flat outdoor running at typical training speeds. Treadmill calibration also varies, so treat the display as approximate.
Where pace comes from: cadence and stride length
Speed is simply cadence (steps per minute) multiplied by stride length (distance per step). At 5:00 per km you cover 200 meters a minute. With a cadence of 170 steps per minute, each step averages 200 ÷ 170 = 1.18 m; at 180 steps per minute it is 1.11 m. Neither is “correct”: taller runners naturally take longer steps, and cadence rises on its own as you speed up.
Still, if you overstride, landing with your foot far ahead of your hips, a small cadence increase of about 5% often smooths things out without changing pace. The stride length calculator works out your stride from steps and distance, so you can see how your own numbers shift between easy runs and faster sessions.
Quick tips for using pace well
- Check seconds, not decimals. 9.5 minutes is 9:30, not 9:50.
- Adjust for heat and hills. On hot, humid days expect to run 10–30 seconds per mile slower at the same effort.
- Use the lap button. GPS pace jumps around under trees and between buildings; average lap pace is steadier than instant pace.
- Retest every 6–8 weeks. Your training paces should come from a recent race or time trial, not last year’s best.
- Fuel for the work. The running calorie calculator estimates what a run burns, and our guide on how many calories you should eat puts that in context.
A note before you lace up: this guide is general information, not personal medical or coaching advice. If you are new to exercise or have a health condition, check with a doctor, and build up gradually. The US Physical Activity Guidelines count 75 minutes a week of vigorous activity such as running as meeting the adult aerobic target.
Frequently asked questions
What is a good running pace for a beginner?
Anything you can sustain while still speaking in short sentences. For many new runners that is 11:00–13:00 per mile (6:50–8:05 per km); speed comes later from consistency, not from forcing the pace.
What is the average 5K pace?
Recreational 5K finish times commonly fall between about 25 and 40 minutes, which is roughly 8:00–13:00 per mile. Age, sex and training history move this a lot, so compare yourself with your own last result.
How do I convert pace per mile to pace per km?
Convert the pace to seconds and divide by 1.609344. For example, 9:00 per mile is 540 seconds; 540 ÷ 1.609344 = 335.5 seconds, or 5:36 per km.
Is 10 minutes per mile a good pace?
Yes, for most recreational runners 10:00 per mile (6:13 per km) is a solid, comfortable training pace. It equals a 31:04 5K or a 4:22 marathon if held throughout.
How accurate are race time predictions?
For neighboring distances, such as 5K to 10K, Riegel-based predictions are usually within a few percent. They become less reliable as the gap grows, especially for the marathon, where training volume matters as much as speed.
Once you know your pace, every run has a clear purpose: easy days genuinely easy, hard days at a number you can measure, and race day split so the last mile is your strongest. Put your latest result into the running pace calculator, write down your training paces, and update them after your next race.