Swim Pace Calculator

How this works

"Swim time → pace" takes a total distance and a total time and normalizes it to a standard pace per 100 (plus per 50 and per 25, for shorter reps). "Pace → set time" runs the math the other way: given a target pace per 100, a rep distance, a number of reps, and rest between reps, it calculates how long the entire set takes — swim time, rest time, and the send-off you'd write on a pace clock. Times can be entered as m:ss or h:mm:ss.

FAQ

Why does it ask for stroke?

Stroke doesn't change the math — it only changes the reference pace ranges shown at the bottom, so you can tell whether your number is a realistic training pace or an elite one. Freestyle is fastest for most swimmers, breaststroke is typically slowest; picking the right stroke keeps that comparison honest.

What's the difference between pace and send-off?

Pace is how long a rep actually takes you to swim. Send-off (sometimes called an interval) is pace plus rest — it's the number written on a workout, e.g. "10x100 on 1:45," meaning you leave the wall every 1:45 whether you finish in 1:25 or 1:40. This tool shows both so you can plan a set around either one.

Why yards and meters instead of just one unit?

US pools are almost always 25 yards (short course yards); most of the rest of the world, plus all Olympic and long-course racing, uses meters. Pace per 100 yards and per 100 meters aren't directly comparable, so matching the unit to your actual pool matters more than it seems.

How accurate are the recreational and competitive ranges?

They're rough, commonly-cited ranges meant to give context, not a benchmark to hit. Pace depends heavily on your training background, the specific stroke, turns, and even the pool itself — treat them as a sanity check on your number, not a target.