Swim Distance & Lap Counter
Count lengths into a total distance for a 25 m, 50 m, or 25 yd pool, in both metres and yards — or flip it around and see how many lengths your target distance needs.
Lengths, laps, and the numbers that matter
Keeping an honest count is half the battle in a long swim. Because pools come in three common sizes — the 25 m short course, the 50 m Olympic pool, and the 25 yd short course used across the United States — the same number of lengths can mean very different distances. This counter fixes the pool length once and does the arithmetic in both metres and yards, so you always know exactly how far you have gone.
Pair it with the Swim Pace Calculator to turn that distance and your time into a per-100 pace, and with the Interval Set Builder to plan a set that adds up to a round total.
Frequently Asked Questions
Is a length the same as a lap?
Not always, and it causes endless confusion. A length is one end-to-end pass of the pool, wall to wall. Some swimmers call that a lap; others use lap to mean there and back — two lengths. This tool counts lengths (one wall-to-wall pass each), because that is what you can actually tally as you swim. If your watch or a workout is written in laps meaning down-and-back, double the number before you enter it.
How many lengths make a mile?
It depends on the pool. A true 1,600 m is 64 lengths of a 25 m pool or 32 of a 50 m pool. The common swimmers' mile of 1,650 yards — a metric mile in yards — is 66 lengths of a 25 yd pool. A land mile of 1,609 m works out to about 64.4 lengths of 25 m, so most people round to 64 or swim 1,650 as a clean target. Enter your distance and pool and the tool gives the exact count.
Why is a 25 yd pool shorter than 25 m?
A yard is 0.9144 metres, so a 25 yard length is only 22.86 metres. Forty lengths of a 25 yd pool is 1,000 yards but only about 914 metres — noticeably less than 1,000 metres of the same number of 25 m lengths. That is why the calculator always shows the total in both metres and yards, so a session in one unit is easy to read in the other.
How do I hit an exact distance target?
Enter your target and pool length in the second mode and the tool divides the distance by the pool length, then rounds up to a whole length — because you finish at a wall, not mid-pool. It also shows the exact fractional lengths so you can see how close a round number gets you, and the actual distance those whole lengths cover.
Distances use the exact 1 yard = 0.9144 m conversion. Confirm your pool’s true length — some older pools are not exactly 25 m or 25 yd.