Enter your distance and time, and get instantly your average speed (km/h), your pace (min/km) and every split, kilometre by kilometre and at the key distances (5 km, 10 km, half, marathon). Whether you're preparing your first race or chasing a PR, mastering your pace is the number-one lever to progress and manage effort.
The calculator
Pace calculator
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Your results
Splits at key distances
| Distance | Time |
|---|---|
| 1 km | 5:00 |
| 2 km | 10:00 |
| 5 km | 25:00 |
| 10 km | 50:00 |
| 15 km | 1:15:00 |
| 20 km | 1:40:00 |
| Half marathon | 1:45:29 |
| Marathon | 3:30:59 |
Splits km by km
| Km | Cumulative time |
|---|---|
| 1 | 5:00 |
| 2 | 10:00 |
| 3 | 15:00 |
| 4 | 20:00 |
| 5 | 25:00 |
| 6 | 30:00 |
| 7 | 35:00 |
| 8 | 40:00 |
| 9 | 45:00 |
| 10 | 50:00 |
Split at a specific distance
Get the projected time for any distance in metres at the same pace.
Pace or speed: what's the difference?
Both measure the same thing, how fast you go, but in two different languages.
Speed is in kilometres per hour (km/h): the distance you'd cover in one hour at that rhythm. It's the unit of treadmills and bikes.
Pace is in minutes per kilometre (min/km): the time you need to cover one kilometre. It's the reference unit for runners and most GPS watches, because it translates directly into splits on the course.
Both are tied by a simple relation: speed (km/h) = 60 ÷ pace (min/km). A 5:00/km pace equals 12 km/h; a 6:00/km pace equals 10 km/h.
How to compute pace and speed
Both formulas fit in one line each:
- Pace (min/km) = total time ÷ distance. For 10 km in 50 minutes: 50 ÷ 10 = 5:00/km.
- Speed (km/h) = distance ÷ time (in hours). For 10 km in 0.833 h (50 min): 10 ÷ 0.833 = 12 km/h.
The classic mistake is mixing minutes and hours. Always convert the total time to seconds first (hours × 3600 + minutes × 60 + seconds), then apply the formula. That's exactly what the calculator above does, error-free.
Concrete examples by distance
| Race | Time | Pace | Average speed |
|---|---|---|---|
| 5 km | 30:00 | 6:00 /km | 10 km/h |
| 10 km | 50:00 | 5:00 /km | 12 km/h |
| Half marathon (21.0975 km) | 2:00:00 | 5:41 /km | 10.55 km/h |
| Marathon (42.195 km) | 4:00:00 | 5:41 /km | 10.55 km/h |
Two takeaways. First, a half in 2 h and a marathon in 4 h run at the same pace (5:41/km): doubling the distance in double the time means holding the same rhythm. Second, marathon pace is almost always slower than 10K pace for the same runner, and that's normal: endurance has a price over time.
Reference pace table
Useful to aim for a target time: find your goal pace and read the projected times directly (at steady pace).
| Pace | Speed | 10 km | Half | Marathon |
|---|---|---|---|---|
| 4:00 /km | 15.0 km/h | 40:00 | 1:24:23 | 2:48:47 |
| 4:30 /km | 13.3 km/h | 45:00 | 1:34:56 | 3:09:53 |
| 5:00 /km | 12.0 km/h | 50:00 | 1:45:29 | 3:30:59 |
| 5:30 /km | 10.9 km/h | 55:00 | 1:56:02 | 3:52:04 |
| 6:00 /km | 10.0 km/h | 1:00:00 | 2:06:35 | 4:13:10 |
| 6:30 /km | 9.2 km/h | 1:05:00 | 2:17:08 | 4:34:16 |
| 7:00 /km | 8.6 km/h | 1:10:00 | 2:27:41 | 4:55:22 |
Why splits matter
Splits are the cumulative times at each marker of the race. They turn an abstract goal ("finish in 50 minutes") into concrete cues on the course ("hit 5 km at 25:00").
Why they're useful:
- Hold your rhythm. Comparing your watch to your split plan tells you in real time if you're too fast or too slow.
- Avoid the too-fast start. Runner's mistake #1. A split plan forces you to rein in the first-km euphoria.
- Manage energy. On a half or marathon, leaving 10 s/km too fast on the first half is paid cash on the second.
The calculator gives you these splits km by km and at the key distances. Write them on your forearm or program them on your watch before the gun.
Pacing tips by distance
5 and 10 km: high pace, but don't sprint off the line. Aim for the first km slightly below your target pace, then stabilize. A negative split (second half faster) is often the best strategy.
Half marathon: regularity wins. Most PRs are run at near-constant pace. Keep a margin on the first 5 km; you'll know past km 15 whether your target was realistic.
Marathon: pacing is everything. A steady pace (or a slight negative split) beats an ambitious start almost every time. The famous 30 km "wall" is often a pacing wall: starting too fast empties the tank too early.
Track your runs in ZON
Strength and GPS runs in one timeline, with AI debrief after every session.
Conclusion
Knowing your pace and your splits turns a "feel-it-out" race into a piloted one. Use the calculator before every key session and every race to set a realistic target, build your split plan, and hold the right rhythm from start to finish.