Swimming has one currency and it is the hundred. Runners think in minutes per kilometre and cyclists in kilometres per hour, but every swimmer on every pool deck reads their watch in minutes and seconds per 100. Enter a distance and a time here and you get that number immediately, along with per 100...
POOL
COMMON DISTANCES
PACE / 100 M
2:00
SPEED
0.833 m/s
1:50 per 100 yd · 1:00 per 50 m · 3.00 km/h · 1.86 mph
Total lengths
60 × 25.00 m
Turns
59
Time per length
0:30
SWOLF
48.0
Stroke rate
36.0 /min
Total strokes
1,080
SPLITS
AT
ELAPSED
REMAINING
150 m
3:00
27:00
300 m
6:00
24:00
450 m
9:00
21:00
600 m
12:00
18:00
750 m
15:00
15:00
900 m
18:00
12:00
1,050 m
21:00
9:00
1,200 m
24:00
6:00
1,350 m
27:00
3:00
1,500 m
30:00
0:00
STEPS
Speed is distance over time: 1,500 m ÷ 1,800 s = 0.8333 m/s
Pace per 100 m is 100 ÷ speed = 100 ÷ 0.8333 = 120.00 s, or 2:00
A 25.00 m pool gives 60.00 lengths, so 60 walls to leave and 59 turns
Pace: 2:00 per 100 m
POOL SIMULATION
Why the wall matters. Every arrow reversal is a turn, and a turn is the one moment in swimming when you are not swimming — you are pushing off a solid wall and gliding. This swim has 59 of them. Shorten the pool and you get more; lengthen it and you get fewer, which is the whole reason the same swimmer posts different times in different pools. The simulation shows the first 4 of 60 lengths, at 11.5× real speed.
THE SAME SWIM IN ANOTHER POOL
Same swimmer, same effort, only the walls change. Bar length is total time, so shorter is faster.
Even-pace model. Splits assume you held one speed throughout, which no real swim does. The turn benefit of 0.8 s is yours to set, not a measurement — it is worth far more to a swimmer with a good push-off than to one who touches and stops, so change it and watch the pool comparison move.
Live simulation · drawn to scale · updates as you type
Pick your pool first — 25 m, 50 m, 25 yd, 33⅓ m or open water. This does not change your pace, but it decides how many lengths and turns the swim contained, and everything about the wall follows from it.
Enter the distance and the time. Time takes h:mm:ss, so 30:00 works for half an hour and 1:02:30 works for a longer swim. Your pace per 100 appears immediately, along with speed, splits and the count of lengths and turns.
Add your strokes per length to get SWOLF and stroke rate. Count the strokes on one comfortable length rather than guessing, and count the same way each time — some swimmers count both arms, some only one, and the number is only useful compared with itself.
Set the seconds you gain per turn, then read the pool comparison on the right. It holds your swimming speed constant and changes only the walls, which is the honest way to compare a short course time with a long course one.
A 1500 m swim in 30:00, in a 25 m pool, at 18 strokes a length. Speed first: 1500 m ÷ 1800 s = 0.8333 m/s. Pace per 100 m: 100 ÷ 0.8333 = 120 s, which is 2:00. The same sum in reverse is the one swimmers do on the wall — 1500 m is fifteen hundreds, and 30:00 ÷ 15 = 2:00 each. Per 100 yards: 100 yd is 91.44 m, so 91.44 ÷ 0.8333 = 109.7 s, or 1:50. The pool: 1500 ÷ 25 = 60 lengths, so 59 walls to turn on and 30 s spent on each length. SWOLF: 30 s + 18 strokes = 48. Stroke rate: 18 ÷ 30 × 60 = 36 strokes per minute. Over 60 lengths that is 1,080 strokes in total. Now the walls. At 0.8 s gained per turn, the 59 turns were worth 47.2 s, so the turn-free swimming time is 1800 + 47.2 = 1847.2 s. Hand that same swimmer a 50 m pool and they get only 29 turns, worth 23.2 s, for a finishing time of 1824.0 s — 30:24, a full 24 seconds slower for identical swimming.
Last updated: July 28, 2026 · Formula verified · Pace and splits are exact; the per-turn benefit is your estimate, not a measurement · Eagle-eyed accuracy for every calculation.