Swim Pace Calculator
Pace per 100, SWOLF and CSSRuns locally · nothing uploaded
Pace
| Distance | Time |
|---|---|
| 50 m | 1:00.0 |
| 100 m | 2:00.0 |
| 200 m | 4:00.0 |
| 400 m | 8:00.0 |
| 800 m | 16:00.0 |
| 1500 m | 30:00.0 |
| 1900 m (Ironman 70.3) | 38:00.0 |
| 3800 m (Ironman) | 1:16:00.0 |
SWOLF efficiency
SWOLF = seconds per length + strokes per length. Lower is more efficient; compare only with yourself in the same pool and stroke.
Critical swim speed (CSS)
CSS is roughly the fastest pace you can hold for about 30 minutes; it's used to set endurance and interval sets. Rest fully between the two trials.
Estimates from general formulas and population averages; individual results vary. For training reference only.
How it works
Formula
Pace per 100 m = time ÷ distance × 100SWOLF = seconds per length + strokes per lengthCSS per 100 m = (400 m time − 200 m time) ÷ 2Worked example
Given: 1500 m in 30:00; trials of 7:20 (400 m) and 3:20 (200 m)
- Pace = 1800 ÷ 1500 × 100 = 120 s, i.e. 2:00 per 100 m.
- CSS = (440 − 200) ÷ 2 = 120 s per 100 m.
Result: Average pace and CSS are both 2:00 per 100 m.
Limitations
- SWOLF depends on pool length, stroke and turns—compare only with yourself.
How to use
- 1Choose meters or yards and enter distance and time to see pace and predictions.
- 2For SWOLF, enter pool length, seconds per length and strokes.
- 3After a 400 m and a 200 m time trial, calculate your CSS pace.
FAQ
What is SWOLF?
Seconds per length + strokes per length, combining speed and efficiency. Lower is better; compare only with yourself in the same pool and stroke.
How do I test CSS?
After a warm-up, swim 400 m all-out, recover fully, then 200 m all-out. CSS pace per 100 m = (400 m time − 200 m time) ÷ 2.
What's a good swim pace?
Recreational freestyle is often 2:00–2:30 per 100 m; under 1:40 is solid, and elite swimmers go under 1:00.