Swim pace
calculator

Enter a distance and a time; get your pace per 100 and per 50, plus even splits, in metres or yards. With the exact yard-to-metre course conversion most swim calculators skip.

How the math works

Swim pace is one identity, read on a per-100 basis because that's how a pace clock reads: time divided by the number of hundreds you swam.

The distance you enter is a plain count of the course unit — 500 means 500 yd in a yards pool, 500 m in a metric pool. Swimming runs on three standard courses: short-course yards (a 25 yd pool), short-course metres (25 m), and long-course metres (50 m), per the World Aquatics facility conventions. The yard-to-metre factor is exact, per NIST SP 811 — no rounding. Because 100 yd = 91.44 m, a 100 yd swim is 8.56 m shorter than 100 m, which is why the per-100 m clock is always the slower-looking number for the same speed.

Worked example

A masters swimmer holds an even effort through a 500 yd freestyle in 7:30 (short-course yards). What's the pace, and what would the same speed read on a metric course?

• Pace per 100 yd: 7:30 (450 s) ÷ 5 = 1:30 / 100 yd (0:45 / 50 yd)
• Same speed, metric course: 90 s ÷ 0.9144 = 98.4 s = 1:38 / 100 m
• Even 100 yd splits: 1:30, 3:00, 4:30, 6:00, 7:30
• Metric cross-check: a 1500 m swim in 24:00 is 1:36 / 100 m, which is 1:28 / 100 yd at the same speed

When this calculator is wrong

Every number here is an estimate, and real-world calibration beats the arithmetic. The per-100 pace and the even-split table assume a constant speed and a single course; your actual timed set on the pace clock is the measurement. The clearest way the math misleads is across pool lengths: converting a pace by distance alone (the × 0.9144 factor) ignores that a 25-length pool has twice the push-off walls of a 50-length pool over the same distance, and a push-off is faster than swimming speed. So a swimmer usually posts quicker short-course times than a distance-converted long-course pace predicts. Calibrate against a real repeat set rather than trusting the converted number; the exception is that a single 100 is noisy — a dive versus a push start, one missed turn — so take the average over the set, not one length.

• Turns aren't in the arithmetic. The 0.9144 conversion is pure distance. Short-course times beat long-course times at the same swimming speed because there are more walls to push off — a real effect the math can't see.
• Even splits are a target, not a plan. The table divides the effort evenly. Most swims carry a fast first length (dive or push start) and drift slower with fatigue; use the splits as a ceiling for the front half, not a promise.
• Course-unit mismatch is the classic error. A "1:30 / 100" means different speeds in a yard pool and a metre pool. Match the toggle to the pool you actually swam, or the pace is off by about 9%.

What to do with the result

Set your working pace from a timed test set, not from a time you hope to hold — swim something like 5 × 100 on a comfortable send-off and read the average off the clock. Use the per-100 number as the target for repeats and the split column as the front-half ceiling for a straight swim. When you travel or switch pools, convert with the exact factor before comparing: your 1:30 / 100 yd is 1:38 / 100 m at the same speed, so a metric pool will read slower even when you're swimming identically. Re-test every few weeks; if the pace you can hold across a full set has moved, that's your new number, not the one you first entered.

Common questions

How do I calculate swim pace per 100?

Divide your time by the number of hundreds you swam. A 500 yd swim in 7:30 is 450 seconds ÷ 5 = 90 seconds, or 1:30 per 100 yd. The same method works in metres: a 1500 m swim in 24:00 is 1:36 per 100 m. This calculator does the division and the per-50 for you.

How do I convert a 100 yard pace to a 100 metre pace?

Divide the per-100 yd time by 0.9144 (the exact yards-to-metres factor). A 1:30 / 100 yd pace is 1:38 / 100 m. Going the other way, multiply the per-100 m time by 0.9144. The per-100 m clock is always slower because 100 m is the longer distance.

Why is my 100 yard time faster than my 100 metre time?

Two reasons. First, 100 yd is only 91.44 m — 8.56 m shorter — so it takes less time at the same speed. Second, most 100 yd swims happen in a 25 yd pool with four walls to push off, versus two in a 50 m pool, and each push-off is faster than swimming. The distance conversion captures the first effect but not the second.

What's a good swim pace per 100 metres?

There's no single number worth citing — it depends on stroke, distance, and training age, and any "average" figure floating around is a made-up benchmark, not a measured norm. The useful comparison is against yourself: time a repeat set now, and watch whether the pace you can hold across the whole set drops over a training block.

How many metres is a 500 yard swim?

457.2 metres (500 × 0.9144). A 1000 yd swim is 914.4 m, and the 1650 yd "mile" is 1508.76 m — close to, but not the same as, the 1500 m metric event. That's why a yard-pool time and a metre-pool time aren't directly comparable without converting.

Does pool length change my pace?

Yes. A shorter pool means more turns over the same distance, and push-offs are faster than swimming, so short-course times are quicker than long-course times for the same fitness. This calculator's course conversion is distance-only, so treat a converted short-course pace as an upper bound on the long-course equivalent.