The trade-off between strokes and seconds
SWOLF adds seconds and strokes as if they were worth the same, so removing one stroke helps it exactly as much as gaining one second. This table starts from your length A and moves one thing at a time, so you can see how much each stroke you save is allowed to cost before it stops being worth it.
| What you change | Time | Strokes | SWOLF | Pace / 100 m |
|---|
Look at the bottom rows: squeezing the time without adding strokes lowers SWOLF and makes you faster, which is the point. Removing strokes at the same time does too, but that almost never comes free. The trap is removing strokes and letting the time drift up: SWOLF can fall while you get slower.
What SWOLF is and what it is actually good for
SWOLF is the sum of the time you take for a length and the number of strokes you take in that length. The name comes from swim golf: as in golf, lower is better. That is all. There is no hidden formula.
What makes it clever is that it punishes both ways of swimming badly at once: being slow, and needing lots of strokes to get anywhere. A swimmer covering 25 m in 21 seconds with 20 strokes has a SWOLF of 41. Same time with 18 strokes, 39. And 19 seconds with the same 20 strokes, also 39.
It is adding seconds to strokes, and you need to know that
A second and a stroke are not the same unit. Adding them means nothing physically: SWOLF is not a speed, not an efficiency, not a percentage of anything. It is an index, and like every index it only makes sense compared with itself.
From that come the three conditions almost nobody respects when comparing SWOLF:
Same pool length. In a 50 you take twice the strokes and more than twice the time, because you are one wall short. The SWOLF of a 50 m length is not double that of a 25: it is rather more.
Same stroke. A length of breaststroke has very few strokes and a lot of time; comparing its SWOLF with freestyle tells you nothing.
Similar speed. The SWOLF of an easy length and of an all-out one are not comparable, not even in the same person on the same day.
The glide trap
Here is the underlying problem, and it is arithmetic: SWOLF drops one point if you remove a stroke, and one point if you gain a second. It treats them as equal. But removing a stroke is almost never free: you stretch out, you glide, you lose speed in the dead spot, and the length costs you half a second or a second more.
Do the break-even sum: removing a stroke pays off in SWOLF terms as long as it costs you less than one second. And in a 25 metre length, for an ordinary swimmer, removing a stroke almost always costs between half a second and a second and a half. So you are sitting right on the boundary, and it is very easy to cross it without noticing.
That is how people spend a winter "improving their SWOLF" and turn up to the first race of the season swimming slower than the year before, with a beautiful, enormously long stroke. It is the classic mistake of reading the index instead of the stopwatch. The table above exists for exactly that: always look at the pace per 100 column, not just the SWOLF one.
The distance per stroke your watch shows you is inflated
Almost every watch works out distance per stroke by dividing the pool length by the strokes in that length. The problem is that you do not swim the first few metres of any length: you cover them on the push-off and the underwater phase, without taking a single stroke.
With 25 metres and 20 strokes, the straight division gives 1.25 m per stroke. If your push-off carries you 5 metres, you actually stroked for 20 metres, and your real distance per stroke is 1.00 m: 25 % less. This calculator gives you the figure with the push-off taken out, which is the one you can compare from day to day and between pools.
It also explains something that puzzles a lot of people: why all your numbers get worse the moment you move to a 50 m pool. You have not got worse — there are simply half as many walls per 100 metres swum.
Of the two factors, which one should you work on?
All speed in the water comes from multiplying two things: how far you go on each stroke by how many strokes you take per minute. If one goes up and the other goes down in the same proportion, you swim at exactly the same speed. That is what the trade-off table is showing you.
Distance per stroke has a ceiling, and the ceiling is set by your wingspan and by how well you can hold water without it slipping. Once you reach it, the only way to go faster is to raise the rate. Pool distance swimmers sit at around 30 to 36 cycles per minute, and sprinters above 50.
As a working rule: if you take a lot of strokes and go nowhere, your margin is in technique and in the catch. If your stroke is already long and you struggle to push the pace, your margin is in the rate. And if you race in open water, be careful: with no walls and with chop, rate matters more than it does in the pool, and a very long, slow stroke punishes itself. You can put numbers on that in the CSS and open water calculator.
Reference figures, with every caveat attached
These bands are for freestyle, in a 25 metre pool, at a comfortable aerobic pace. Outside those three conditions they do not apply, and even inside them there are tall swimmers with a high SWOLF who are very fast indeed. Use them to place yourself, not to judge yourself.
| Level | SWOLF over 25 m | Typical strokes |
|---|
| Beginner | 50 – 60 | 26 – 34 |
| Recreational triathlete | 42 – 50 | 22 – 28 |
| Solid age grouper | 36 – 42 | 18 – 24 |
| Competitive | 30 – 36 | 16 – 20 |
| Club swimmer | under 30 | 14 – 18 |
The only thing that really helps you is your own series of numbers across the months, always in the same pool and at the same intensity. A SWOLF that drops three points over a season and a pace per 100 that drops too: that is improvement.
Frequently asked questions
What is SWOLF in swimming?
It is the sum of the time in seconds for a length and the number of strokes you took in that length. Swim 25 metres in 21 seconds with 20 strokes and your SWOLF is 41. The name comes from swim golf and, as in golf, lower is better.
What is a good SWOLF?
It depends on the pool, the stroke and the intensity, so there is no universal figure. In freestyle, a 25 metre pool and an aerobic pace, a recreational triathlete usually sits between 42 and 50, a solid age grouper between 36 and 42, and a club swimmer below 30. Comparing your SWOLF with someone else's is worth little; comparing it with your own from three months ago is worth a lot.
Can your SWOLF drop while you swim slower?
Yes, and it is the most common mistake. Since the index takes off one point for a stroke saved just as it does for a second saved, stretching out and gliding removes strokes but costs time. As long as each stroke you save costs less than one second, SWOLF falls; the moment it costs more, your speed falls and SWOLF rises. That is why you always have to read the pace per 100 next to it.
Why does my SWOLF get worse in a 50 m pool?
Because there are half as many walls per 100 metres swum, and the push-off is the fastest part of any length. You take more strokes and you take more than twice as long as in a 25. It is normal and says nothing about your form: you just must not mix the two sets of numbers.
Do I count strokes or cycles?
Garmin watches and most apps count one stroke per hand entry, so two per full cycle. Many coaches count cycles. Either works as long as you are consistent, but SWOLF comes out very differently: counting cycles, your number will be roughly 20 points lower. The selector above handles it.
What is distance per stroke and what is normal?
It is how far you travel on each stroke, and in freestyle it runs from about 0.8 m for beginners to over 1.5 m for tall, technical swimmers. Be careful with the figure your watch gives you, because it divides the whole length by the strokes and includes the push-off metres you did not swim. With the push-off taken out the number drops by around 20 to 25 %, and that is the one you can compare between pools.
Is SWOLF any use in open water?
Not much, because there are no lengths and no walls, and the watch cannot count them. What does carry over is the lesson: in open water, with no push-off and with chop, stroke rate matters more than it does in the pool, and very long slow strokes get punished. Many swimmers deliberately raise their rate when they go to sea.
How much should my SWOLF drop in a season?
Two or three points in a 25 metre pool is a real, noticeable improvement if it comes with an equal or better pace per 100. Much bigger drops over a few weeks almost always mean you changed the intensity of the test or the way you count, not that you improved that much.
