🏊 Swim Pace Calculator

Enter a swim distance and time to calculate your pace per 100m/yd and average speed.

Distance

Unit

Time (mm:ss or hh:mm:ss)

Seconds per unit, scaled to 100

The time string is parsed to seconds, divided by the distance and multiplied by a hundred. Average speed is the same division turned the other way up:

pace per 100 = total seconds / distance × 100
speed = distance / total seconds × 60   (per minute)

1000 m in 18:00 is 1080 seconds, so 108 seconds per 100 m - a 1:48 pace - at 55.6 m/min. Halve it to 500 m in 9:00 and both figures are unchanged, since pace is independent of distance.

Entering and reading it

The time needs a colon. mm:ss or hh:mm:ss; 18 on its own is rejected, and a long open-water swim goes in as 1:12:30.
Pace is rounded to whole seconds. A true 1:48.4 and a 1:47.6 both display as 1:48, so this will not settle a tenths-level comparison between two sets.
Only continuous swimming counts. Feed it a set of 10 x 100 with rest and the pace includes the wall time, not your repeat pace.

The unit box is a label, not a conversion. Yards and metres are never translated into each other, and 100 m is 9.4% further than 100 yd - the 1:48 above would be about 1:39 per 100 yd at the same speed.

Frequently asked questions

How do I calculate swim pace per 100m?

Divide your total time in seconds by the distance, then multiply by 100. 1080 seconds over 1000 m gives 108 seconds, written 1:48.

How many lengths is 1000 metres?

Forty lengths of a 25 m pool, or twenty of a 50 m pool. A 25 yd pool also takes forty lengths for 1000 yards, but that is a shorter swim.

What speed is a 1:48 per 100m pace?

About 55.6 metres a minute, or 3.3 km/h. Swim speeds look small beside running because drag in water rises steeply with pace.