Swim SWOLF Calculator
Swim efficiency score with 100 m pace.
What it does
SWOLF golfifies swimming. Strokes plus seconds per length rewards holding pace with fewer pulls. Two swimmers at 2:00 per 100m split clearly when one takes 80 strokes and the other 100.
The tool above scores one length and projects both rates. With 20 strokes in 30 s over 25 m, SWOLF is 50 with 2:00 per 100m and 80 strokes per 100m. A 50 m case at 35 strokes in 55 s gives 90 SWOLF with 1:50 per 100m. Same pace, lower score wins.
Pool size scales the projections. Strokes and seconds both multiply by 100 over pool length, so 25 and 50 m mornings compare fairly. Turns and walls flatter pool numbers, which is why open water feels harder at equal SWOLF.
This page scores efficiency only. It does not coach catch, kick, or breathing. Film strokes beside the score before changing technique.
How to use
- Pick the 25 or 50 m pool.
- Enter strokes for one length.
- Enter seconds for that length.
- Read SWOLF first.
- Read 100 m pace and strokes.
- Compare at matched pace across weeks.
Formula
- pool
- Pool length, 25 or 50 m.
- strokes
- Arm cycles counted for one length.
- seconds
- Seconds for that same length.
Per length score combining technique with speed. At zero seconds there is no pace; very high stroke counts signal short choppy strokes. Turns and push offs flatter pool scores versus open water.
Worked example
Example: 20 strokes in 30 s
Defaults: 25 m pool with 20 strokes in 30 s. SWOLF adds strokes to seconds.
- Inputs: 25 m pool with 20 strokes in 30 s.
- SWOLF: 20 plus 30 is 50 SWOLF.
- Pace: 30 times 100 / 25 is 120 s, or 2:00 per 100m.
- Strokes: 20 times 100 / 25 is 80 strokes per 100m.
- Lower wins at equal pace. Tool shows the same.
Reference table
| Length | SWOLF | Pace |
|---|---|---|
| 25 m, 20 in 30 s | 50 SWOLF | 2:00 per 100m |
| 50 m, 35 in 55 s | 90 SWOLF | 1:50 per 100m |
| 25 m, 15 in 25 s | 40 SWOLF | 1:40 per 100m |
| 50 m, 40 in 60 s | 100 SWOLF | 2:00 per 100m |
| 25 m, 25 in 35 s | 60 SWOLF | 2:20 per 100m |
Limits
- Pool only. Open water differs.
- One length assumed. Pace changes excluded.
- No technique model. Film needed.
- Turns included. Long course differs.
Common mistakes
- Comparing 25 m with 50 m scores directly.
- Gliding into walls to cut strokes.
- Sprinting seconds while ignoring stroke count.
- Reading SWOLF without pace context.
- Changing two technique cues at once.
Try it yourself
Quick checks. Answers sit tucked under each question.
50 m pool, 35 strokes in 55 s?
SWOLF is 35 plus 55 is 90 SWOLF. Pace is 110 s, or 1:50 per 100m, with 70 strokes per 100m.
25 m pool, 15 strokes in 25 s?
SWOLF is 15 plus 25 is 40 SWOLF. Pace is 100 s, or 1:40 per 100m, with 60 strokes per 100m.
Questions
How is SWOLF figured?
Strokes plus seconds per length. Here 50 SWOLF.
Is lower better?
Lower at the same pace. Fewer strokes with equal time means longer, cleaner strokes.
How is 100 m pace figured?
Seconds times 100 / pool. Here 2:00 per 100m.
Does pool size matter?
Yes. Pick 25 or 50 m to match the pool.
Does this work in open water?
No. Turns, push offs, and drafting shift pool SWOLF from open water.
How do I use this in training?
Track both across weeks. Falling SWOLF at fixed pace means better economy.