Swim Interval & Send-Off Calculator
Turn a pace into send-offs for every repeat distance, add up the yardage and clock time of a set, and get training paces from a CSS test — built for coaches writing practice, and swimmers training on their own.
Seconds (90) or minutes (1:30).
| Repeat | Swim time | Rest | Send-off |
|---|---|---|---|
| 25 yd | :20 | :10 | :30 |
| 50 yd | :40 | :10 | :50 |
| 75 yd | 1:00 | :10 | 1:10 |
| 100 yd | 1:20 | :10 | 1:30 |
| 150 yd | 2:00 | :10 | 2:10 |
| 200 yd | 2:40 | :10 | 2:50 |
| 300 yd | 4:00 | :10 | 4:10 |
| 400 yd | 5:20 | :10 | 5:30 |
| 500 yd | 6:40 | :10 | 6:50 |
Writing intervals that work
A good interval gives a swimmer a specific amount of rest at a specific pace. Start from the pace you want the set swum at, decide how much rest the set calls for — a few seconds for threshold work, as much as the swim itself for sprint work — and let the calculator round to the pace clock.
When a group swims together, set the interval from the slowest swimmer you want making it, or split lanes by CSS so every lane gets the rest the set was designed for.
Training zones from CSS
CSS-based zones are offsets from threshold pace: endurance work sits a few seconds per 100 slower, race-pace work a few seconds faster. The ranges here follow common coaching guidance and are a starting point to adjust to your swimmers, not a prescription.
Frequently asked questions
More free swim tools
Swam in a different pool? Convert times between SCY, SCM and LCM.
Plan practice where your team already lives
CoachBrighter lets you build practices set by set, with intervals, and keep the season’s plan next to your roster, meets and results.