Running pace·3:55 /km
3:55
/km · 15.32 km/h

3:55 per km — marathon in 2:45:16, 15.32 km/h

Running 3:55 per kilometre is 15.32 km/h. Hold it and the half comes in at 1:22:38, the marathon at 2:45:16.

Finish times

These assume you hold the pace from gun to tape. Most runners drift slower in the second half, so leave a margin when setting a target.

5K
19:35
10K
39:10
Half
1:22:38
Marathon
2:45:16
Speed
15.32 km/h
Metres per second
4.255 m/s
Pace per mile
6:18
One lap (400 m)
1:34

What this pace breaks

The cut-offs are tighter than they look: a sub-4 marathon needs 5:41 per kilometre, and one second slower puts you over four hours.

sub-20 min 5K · yessub-25 min 5K · yessub-30 min 5K · yessub-50 min 10K · yessub-60 min 10K · yessub-100 min Half · yessub-2h Half · yessub-3h Marathon · yessub-3:30h Marathon · yessub-4h Marathon · yessub-5h Marathon · yes

Nearby paces

Pace per kmHalfMarathon
3:501:20:522:41:45
3:511:21:142:42:27
3:521:21:352:43:09
3:531:21:562:43:51
3:541:22:172:44:34
3:551:22:382:45:16
3:561:22:592:45:58
3:571:23:202:46:40
3:581:23:412:47:22
3:591:24:022:48:05
4:001:24:232:48:47

The half and the full are not round numbers

A marathon is 42.195 km and a half is 21.0975 km. Rounding to 42 km costs you about a minute at a 5:00 pace — small, but enough to miss a target.

How to read this

  • Pace is the time for one kilometre, so a smaller number means faster.
  • To get speed, divide 3600 by the pace in seconds: 300 s gives 12 km/h.
  • A finish time is simply the pace multiplied by the distance.
  • Mile pace is kilometre pace times 1.609344.

Frequently asked questions

Q. What marathon time does 3:55 per km give?

2:45:16. The half comes in at 1:22:38, the 10K at 39:10 and the 5K at 19:35.

Q. How fast is 3:55 per km in km/h?

15.32 km/h, or 4.255 metres per second.

Q. What is that per mile?

6:18, because a mile is 1.609344 km.

Q. And one lap of the track?

1:34 for 400 m.