Swimming Time Converter
Compare pool courses. Understand your turns. Put your time in context.
Your Course Estimate
for 100 m
+0.80 sec vs entered time
60.00 s + (3 − 1) × 0.40 s = 60.80 s
Illustrative turn model · Not an official qualifying time.
Pool Course Comparison
Source · 25 m SCM
100 m · 4 lengths · 3 turns
Target · 50 m LCM
100 m · 2 lengths · 1 turn
Two fewer turns in the target course · 0.80 sec model adjustment.
Schematic pool illustrations · not to scale.
Turn Adjustment by Event
| Event | SCM turns | LCM turns | Turn adjustment |
|---|---|---|---|
| 50 m | 1 | 0 | +0.40 s |
| 100 m | 3 | 1 | +0.80 s |
| 200 m | 7 | 3 | +1.60 s |
| 400 m | 15 | 7 | +3.20 s |
Same entered turn factor; not predicted race times.
Calculation & Assumptions
For equal distances:
Estimate = entered time + (source turns − target turns) × turn factor.
Turns = event distance ÷ pool length − 1.
Yard events require distance normalization; forecasts remain estimates.
Yards and model details
For different physical distances: estimate = (entered time + source turns × factor) × (target metres ÷ source metres) − target turns × factor. One yard is 0.9144 m. This assumes a constant underlying swimming pace; it does not model fatigue, starts, strokes or individual underwater performance.
Event pairs: 50/50, 100/100, 200/200, 400 m/500 yd, 800 m/1000 yd and 1500 m/1650 yd. Yards and metres are different race distances. This is a planning model, not an official qualifying-time conversion.
Frequently Asked Questions
Why is the adjustment based on the turn difference?
In 100 m, a 25 m pool has four lengths and three turns, while a 50 m pool has two lengths and one turn. The difference is two turns. At an assumed 0.40 sec per turn, the model adds 0.80 sec for short to long course. Starts and the final touch are not turns.
Can I compare yards and metres?
Yes, as a simplified planning estimate. The source and target race distances are shown explicitly and converted to metres internally. The model scales the entered time and source-turn allowance by the physical distance ratio, then subtracts the target-turn allowance. This assumes a constant underlying swimming pace; it is not a validated performance-equivalence table.
Is this an official conversion?
No. The turn factor is your editable assumption, not a World Aquatics or USMS coefficient. Stroke, starts, fatigue, underwater technique and meet-specific rules can affect actual results. Use the governing body or meet organizer’s accepted procedures for official entries.
Sources & References
Pool standards25 m and 50 m course regulations.
Course terminologySCM, LCM and SCY pool conventions.Short to long courseTurns and underwater context.References provide pool and training context. The editable turn model is an ST assumption; no institutional endorsement is implied.
Compare pool courses. Understand your turns. Put your time in context.