A 100-meter race in a short course pool is not exactly the same as a 100-meter race in a long course pool. The turns, the number of strokes, and the actual length of the lane all affect the final time.
The converter above serves three purposes: converting a length measurement into distance, estimating a time based on a pace, and converting a lap time from one pool size to another.
[pa_tool slug="swimming-length-converter"]For swimmers, Protéalpes also offers a calculator to estimate calories burned based on the distance swum, as well as an article on the best whey protein for swimming.
Why aren't all pool lengths the same?
There are three pool standards used in swimming:
- the 25-meter short-course pool (SCM),
- the 50-meter long-course pool (LCM),
- the 25-yard pool used primarily in North America (SCY, short course yards).
The same swimmer will post different times depending on the pool, even when exerting the same effort, due to the number of turns made over a given distance.
Over 400 meters, for example, a large pool requires 7 turns, while a small pool requires 15. Each turn involves a phase of pushing off and gliding underwater, which is generally faster than swimming on the surface. The number of turns accounts for most of the difference in speed between the pools, more so than endurance or swimming technique itself.
This difference is evident in the world records for freestyle: in the 400-meter event, the gap between the long-course record (3:39.96, Lukas Märtens) and the short-course record (3:32.25, Yannick Agnel) exceeds 7 seconds, even though the distance is exactly the same.
| Distance | 50-meter Long Course Pool — Men | 50-meter main pool — Women | 25-meter short course — Men | 25-meter short course — Women |
|---|---|---|---|---|
| 50 m | 20.88 — Cameron McEvoy | 11:55 p.m. — Gretchen Walsh | 19.90 — Jordon Crooks | 22.83 — Gretchen Walsh |
| 100 m | 46.40 — Pan Zhanle | 51.68 — Marrit Steenbergen | 44.84 — Kyle Chalmers | 49.93 — Kate Douglass |
| 200 m | 1:42.00 — Paul Biedermann | 1:52.23 — Ariarne Titmus | 1:38.61 — Luke Hobson | 1:49.36 — Mollie O’Callaghan |
| 400 m | 3:39.96 — Lukas Märtens | 3:54.18 — Summer McIntosh | 3:32.25 — Yannick Agnel | 3:50.25 — Summer McIntosh |
| 800 m | 7:32.12 — Zhang Lin | 8:04.12 — Katie Ledecky | 7:20.46 — Daniel Wiffen | 7:54.00 — Lani Pallister |
| 1500 m | 14:30.67 — Bobby Finke | 3:20:48 p.m. — Katie Ledecky | 14:06.88 — Florian Wellbrock | 3:08.24 p.m. — Katie Ledecky |
Common Distances
Useful reference points: 1 km, 1,500 m, typical triathlon distances, etc.
| Objective | 25-meter pool | 50-meter pool |
|---|---|---|
| 500 m | 20 laps | 10 laps |
| 750 m | 30 laps | 15 laps |
| 1000 m | 40 laps | 20 laps |
| 1500 m | 60 laps | 30 laps |
| 1900 m | 76 lengths | 38 lengths |
| 3000 m | 120 laps | 60 laps |
| 3800 m | 152 lengths | 76 lengths |
Meters to Yards Conversion Chart
The conversion between meters and yards is based on a fixed factor: 1 yard equals 0.9144 meters. Therefore, 25 yards is approximately 22.86 meters, and 100 yards is 91.44 meters.
[pa_tool slug="meter-to-yard-converter"]This difference in length, when accumulated over an entire session, explains the discrepancy between the times displayed on a GPS watch calibrated in meters and the times recorded in a pool measured in yards.
Should you adjust your pace to tailor a workout?
Swimming pace is measured in minutes and seconds per 100 meters. Converting this pace from one pool to another allows you to create training sets that align with your race goal, without relying on a misleading raw time.
A triathlete training for an open-water event would benefit from converting their short-course times to long-course equivalents, which more closely mimic actual competition conditions, where turns are eliminated.
The pace calculation takes into account the total distance and the timed interval, then scales the result to a 100-meter basis. This standardization makes it easier to track progress over several weeks, even when regularly switching training pools. This allows beginners to track their progress using consistent benchmarks, regardless of the session’s pace or the training location.
Common Errors During Conversion
A common mistake is to apply a linear conversion factor to the total time without taking into account the number of turns. This approach consistently underestimates the actual difference between the short course and the long course over long distances.
Another common mistake involves forgetting the conversion factor: yards to meters and meters to yards do not use the same conversion factor, and reversing them completely distorts the displayed result.
