Swim Interval Pace Calculator

About this calculator

Swim interval training uses a send-off interval — a fixed total time for each repeat that bundles together the swim time and the rest — so that a swimmer who swims faster automatically gets more rest before the next rep starts, while a swimmer who swims slower gets less, which is what keeps the set structured around a clock rather than a stopwatch reset after every repeat.

Swim coaches and masters swimmers use send-off intervals to program sets on a pool deck pace clock, since calling out a fixed send-off time is far more practical during a workout than timing rest individually after every single repeat, and knowing the total set duration up front helps fit a workout into an available pool time slot.

This calculator takes your swim time per repeat, target rest time and number of reps, and returns the send-off interval to use and the total time the full set will take.