Swim time converter

25 m pool is short course (SCM). Most winter meets in Portugal are here.
50 m pool is long course (LCM). The big spring and summer meets. Times are slower here. That's the pool, not your swimmer.
25 yd pool is yards (SCY). Mostly in the US. You only need it to compare a time swum there.
Why the gap? Turns. Every wall is a free push. A 100 m race has three turns in a 25 m pool and one in a 50 m pool.
Rule of thumb: long course is about 1 to 2 seconds slower per 100 m.
It's a good guess, not a promise. Swimmers with strong turns often beat it. Swimmers still learning turns often come in behind it.

Can I enter a meet with a converted time?

Sometimes. Some meets accept them and some want a time swum in that pool. Check the meet rules, or ask the coach.

How accurate are converted times?

For most age-group swims, within about a second per 100 m. Good for comparing, not for predicting.

What do SCM, LCM and SCY mean?

Short course metres (25 m pool), long course metres (50 m pool) and short course yards (25 yd pool). Portugal races in the first two.

Why does the 400 m free turn into a 500 yd time?

Yards pools race different distances. The 500, 1000 and 1650 yd are the closest match to the 400, 800 and 1500 m.

Yards times are multiplied by 1.11 to get a 25 m time. Going from 25 m to 50 m adds a small turn allowance for every 50 m of the race. Example: 1:10.00 for the 100 m free in a 25 m pool becomes 1:11.60 in a 50 m pool. This is the standard factor model used by most timing and team software.

Show the factors

Turn allowance added per 50 m, short course to long course
Stroke	Seconds per 50 m
Butterfly	0.70
Backstroke	0.60
Breaststroke	1.00
Freestyle	0.80
Medley	0.80

Yards multipliers
Event	Multiplier
All other events	× 1.11
400 m ↔ 500 yd freestyle	× 0.8925
800 m ↔ 1000 yd freestyle	× 0.8925
1500 m ↔ 1650 yd freestyle	× 1.02

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What you need to know

Quick questions

How the math works

Converted times