Swim Pace Calculator

What this calculator does

This tool converts a swim distance and total time into your pace per 100 metres or yards, then builds a split-time table projecting that pace across common training and race distances. Enter your unit (metres or yards), the total distance you swam, and your total time in seconds, and it returns your formatted pace, the pace in raw seconds, and a table of split times for 100 through 1,500.

Why pace per 100 instead of per mile

Running pace is conventionally measured per mile or kilometre, but pool swimming is built around lap lengths — 25 m, 50 m or 25 yd, depending on the pool — so swimmers and coaches almost universally track pace per 100 metres or yards instead, a distance that divides evenly into most standard training sets and race distances. This is the same framing used by swim-training references like USMS.org's published pace charts, which is why this calculator follows that convention rather than adopting a per-mile pace like the hub's running tools use.

The calculation

Pace per 100 = (total time ÷ total distance) × 100, expressed in seconds and then formatted as minutes:seconds for readability. The split table then scales that same pace up to standard distances — 100, 200, 400, 800 and 1,500 — by multiplying the per-100 pace by each distance divided by 100. This assumes a constant, even pace across the full distance you swam; a swim with significant fade or a fast start won't have a perfectly uniform pace throughout, so the split table represents an average-pace projection, not necessarily what each individual 100 actually looked like during the swim.

Metres versus yards matters

A 25-yard pool is shorter than a 25-metre pool (about 8% shorter), so entering the same total-distance number under a different unit produces a materially different actual distance and therefore a different real pace. Always select the unit that matches the pool you swam in — the calculator doesn't convert between metres and yards, since mixing them would misrepresent your actual pace.

Using this for open-water swimming

You can run open-water swim data through this calculator to get a pace figure, but treat it as a rougher estimate than a pool result. Currents, drafting off other swimmers, and the time spent sighting a course all affect open-water pace in ways a controlled pool swim doesn't experience, so an open-water pace isn't a precise pool-equivalent — use it as a general reference for that specific swim rather than a like-for-like comparison to pool training paces.

This tool gives a general calculation from your entered time and distance. It is not medical advice — check with a qualified coach or medical professional before starting a new swim training program.