Running Pace Calculator
Enter a distance and the time it took (or the time you're targeting), and this calculator returns your running pace per kilometre and per mile, along with your speed in km/h and mph. Use it to check a race result, plan a training run, or work out the pace you need to hit a goal finish time.
How this calculation works
Pace is simply your total time divided by distance covered, expressed as minutes and seconds per unit distance: seconds per km = total seconds ÷ kilometres. The per-mile pace converts that using 1 mile = 1.609344 km.
Speed is the inverse relationship, expressed as distance per hour instead of time per distance: km/h = distance ÷ (total seconds ÷ 3600). Mph is speed in km/h divided by 1.609344.
Pace and speed carry the same information in two different shapes — runners tend to think in pace ("I run 5:00 per km"), while speed is more familiar from cars and bikes ("I run 12 km/h"). This calculator gives you both so you can use whichever your training plan, watch, or treadmill displays.
Worked example
Pace vs. speed: same run, two units
Runners and race organisers almost always talk in pace — minutes and seconds per kilometre or mile — because it maps directly onto splits on a race clock: if your goal pace is 5:00/km, you know you should pass each kilometre marker on the 5, 10, 15-minute mark, and so on. Speed (km/h or mph) is the same information turned upside down, and it's more familiar from treadmill displays, cycling computers, and everyday driving.
Neither is more "correct" — pick whichever matches the tool you're pacing off. This calculator gives you both from a single distance-and-time entry, so you can check a treadmill speed setting against a known race pace, or convert a watch split into km/h.
Finish time by pace and race distance
Use this table to sanity-check a goal pace against common race distances, or work backwards from a finish-time goal to the pace you'll need to hold.
| Pace | 5K | 10K | Half marathon | Marathon |
|---|---|---|---|---|
| 4:00 /km | 20:00 | 40:00 | 1:24:23 | 2:48:47 |
| 4:30 /km | 22:30 | 45:00 | 1:34:56 | 3:09:53 |
| 5:00 /km | 25:00 | 50:00 | 1:45:29 | 3:30:59 |
| 5:30 /km | 27:30 | 55:00 | 1:56:02 | 3:52:04 |
| 6:00 /km | 30:00 | 1:00:00 | 2:06:35 | 4:13:10 |
| 6:30 /km | 32:30 | 1:05:00 | 2:17:08 | 4:34:16 |
| 7:00 /km | 35:00 | 1:10:00 | 2:27:41 | 4:55:22 |
Pacing strategy: even splits and negative splits
- Even splits: run every kilometre or mile at essentially the same pace, which keeps effort predictable and is the easiest strategy to plan and pace off a watch.
- Negative splits: run the second half of the race faster than the first, most often by starting 5–10 seconds/km slower than goal pace to conserve glycogen, then closing the gap in the back half.
- Positive splits: the second half is slower than the first — usually unintentional, and the classic sign of starting too fast and fading, though experienced runners sometimes accept a small positive split on hilly or hot-weather courses.
- Long-run practice: rehearsing your target race pace in training (not just easy miles) builds the pacing sense you'll need to hold it under race-day adrenaline.
Using pace to plan a race
Work backwards from your goal finish time: divide it by the race distance to get your required average pace, then check the table above (or plug your own distance and time into the calculator) to see if that pace is realistic given your recent training paces. Many runners hold their easy-run pace on race day for a half marathon or marathon, and something noticeably faster only for a 5K or 10K, because shorter races draw more on speed and less on endurance.