How is swimming pace per 100m calculated?

The tool divides your total time by the number of 100m segments in your distance. For 1500m in 30:00 that is 1800 seconds ÷ 15, giving 120 seconds, or 2:00 per 100m.

What do the 25m and 50m splits show?

They show the time you should hit at each pool length so you can pace evenly. In a 25m pool one length is a quarter of your 100m pace; in a 50m pool it is half. Hitting these splits keeps you on track for your goal.

Does this estimate my Critical Swim Speed?

For a sustained effort of 800m or more, your per-100m pace closely approximates your CSS, the threshold pace you can hold for a long time. For a precise CSS, use two timed trials and our dedicated CSS calculator.

Should I pace evenly or negative split?

Even pacing is the simplest way to hit a target time and is what the split table assumes. Experienced swimmers often negative-split, starting slightly slower and finishing faster, which feels easier and can produce the same or better time.

Does pool length affect my time?

Yes. Short-course (25m) pools have more turns and pushes off the wall, which usually make times slightly faster than long-course (50m). The splits here help you pace either format toward the same total time.

Swimming Pace Calculator

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Swimming pace calculator

Set a goal time for any swim distance and this tool tells you exactly what pace and per-length splits you need. It computes your pace per 100 metres — the universal unit of swim pacing — and builds a split table for both 25 m and 50 m pools so you can read the wall clock and stay on target during a set.

How it works

Pace per 100 m is simply your total time divided by the number of 100 m segments:

pace per 100m = total time ÷ (distance ÷ 100)

From that single figure the tool derives every split: a 25 m length is a quarter of the 100 m pace, a 50 m length is half, and 200 m or 400 m splits are multiples. Everything is formatted as minutes and seconds.

Example and notes

A 1500 m goal of 30:00 is 1800 s ÷ 15 = 2:00 per 100 m, meaning 30 s per 25 m length or 1:00 per 50 m length. For a sustained effort of 800 m or more, this pace is a good first approximation of your Critical Swim Speed; for a precise threshold figure, run two time trials through the CSS calculator.

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