SWOLF Calculator

1. Swim one length and time it in seconds.
2. Count the strokes you took over that length.
3. Enter both, and choose your pool length.
4. Read your SWOLF score and the per 25 metre value.

SWOLF is a measure of swimming efficiency, named from swim and golf because, like golf, a lower score is better. It adds the time in seconds to swim a length to the number of strokes you took over that same length.

The idea is that good swimming balances speed and effort. You could take fewer strokes by gliding, but too slowly, or thrash quickly with many strokes. SWOLF rewards covering the length fast and with few strokes at the same time, which is the mark of efficient technique. It is the number most swim watches quietly track lap after lap, and watching it drift downward over a season is one of the most satisfying signs that hours of drills and stroke work are actually paying off in the water.

1. Time a single length in seconds.
2. Count your strokes over that length.
3. Add the two together for your SWOLF score.
4. For a 50 metre pool, halve the score to compare it with a 25 metre one.

Because it combines both numbers, SWOLF cannot be improved just by gliding or just by sprinting; you have to lower both time and strokes together. That is exactly why it is a fairer measure of technique than either number alone: a swimmer can always cut strokes by gliding lazily or drop their time by thrashing, but only genuinely better technique moves both in the right direction at once.

You swim a 25 metre length in 30 seconds and take 20 strokes. Your SWOLF is 30 plus 20, which is 50. Improve your technique so the same length takes 26 seconds and 18 strokes, and the score drops to 44, a clear efficiency gain. In a 50 metre pool a length of 45 seconds and 42 strokes gives 87, or about 44 per 25 metres. The two pools give the same underlying efficiency once normalised, which is why a smartwatch will often quote SWOLF per 25 metres regardless of the pool you are actually swimming in. That normalisation is the small detail that lets a swimmer compare a session in a 50 metre competition pool against an everyday 25 metre local pool without the numbers misleading them.

Stroke Length

A longer, more powerful stroke covers the length in fewer strokes, lowering SWOLF.

Speed

Swimming the length faster lowers the time part of the score.

Technique

Better body position and timing improve both speed and stroke count at once.

Stroke Type

SWOLF differs between freestyle, breaststroke and other strokes, so compare like with like.

Rough SWOLF per 25 metres for freestyle by level.

These are broad guides; your own trend over time matters more than an exact number.

Tracking Technique

Watch your SWOLF fall as your stroke becomes more efficient.

Comparing Sessions

Check whether a drill or change has improved your efficiency.

Setting Goals

Aim to lower your SWOLF by improving both speed and stroke length.

1. Only Reducing Strokes

Gliding to cut strokes while slowing down does not lower SWOLF; balance both.

2. Comparing Pool Lengths

A 50 metre SWOLF is naturally higher; normalise to 25 metres to compare.

3. Mixing Strokes

SWOLF varies by stroke, so compare only the same stroke.

4. Chasing One Number

Focus on your own downward trend, not a single benchmark.

The score is exact for the time and strokes you enter. It is a relative efficiency measure, best used to track your own progress.

SWOLF, from swim and golf, is a measure of efficiency: the time in seconds to swim a length plus the strokes taken. A lower score is better.

Add your length time in seconds to your stroke count for that length. A 25 metre length in 30 seconds with 20 strokes is a SWOLF of 50.

For freestyle over 25 metres, under 30 is excellent, 30 to 40 is good, 40 to 50 is average and over 50 has room to improve.

Because it rewards covering the length both fast and with few strokes, the balance of speed and efficiency that marks good technique.

Lengthen and strengthen your stroke to cut strokes, while keeping or improving your speed. Improving both together lowers the score.

Yes. A 50 metre length gives a higher raw score than 25 metres, so normalise to 25 metres to compare across pools.

Not directly. SWOLF varies by stroke, so compare only the same stroke, such as freestyle to freestyle.

They estimate length time and count strokes automatically, then add them, giving the same SWOLF score per length.

No. The calculator runs entirely in your browser and nothing you enter is stored or sent anywhere.

• SWOLF and swim efficiency (Wikipedia).
• Front crawl technique (Wikipedia).
• Stroke rate (Wikipedia).