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Clinical Tools Library · Sports & exercise
Swim Time Converter — SCY · SCM · LCM
Convert a race time between a 25-yard, 25-metre and 50-metre pool using the standard course-conversion factors, and see exactly where every hundredth of the difference comes from.
Converted time
—
Confirm the race details to calculate.
Estimate — not an official time
Where the difference comes from
Each lane is drawn to scale. The gold bars are walls: every wall is a push-off, and a push-off is faster than swimming.
The maths, shown
Independent check & race detail
- Status
- —
Even-pace splits in the target course
| Segment | Cumulative | Segment time |
|---|---|---|
| — | ||
Distance factors
| Conversion | Factor | Notes |
|---|---|---|
| SCY ↔ SCM, 50–200 | 1.11 | Distance only; wall count is identical |
| SCY ↔ LCM, most events | 1.11 | Increment applied for 50–400 |
| 500 y ↔ 400 m, 1000 y ↔ 800 m (LCM) | 0.8925 | No increment |
| 1650 y ↔ 1500 m (LCM) | 1.02 | No increment |
| 500 y ↔ 400 m, 1000 y ↔ 800 m (SCM) | 0.875 | Pure distance ratio; same walls |
| 1650 y ↔ 1500 m (SCM) | 0.997 | Pure distance ratio; same walls |
| SCM ↔ LCM | 1.00 | Distance unchanged; increment only |
Turn increment by stroke
| Stroke | Per wall | 50 | 100 | 200 | 400 |
|---|---|---|---|---|---|
| Backstroke | 0.60 | 0.60 | 1.20 | 2.40 | — |
| Butterfly | 0.70 | 0.70 | 1.40 | 2.80 | — |
| Freestyle | 0.80 | 0.80 | 1.60 | 3.20 | 6.40 |
| Individual medley | 0.80 | — | 1.60 | 3.20 | 6.40 |
| Breaststroke | 1.00 | 1.00 | 2.00 | 4.00 | — |
Distance events (500 y / 1000 y / 1650 y ↔ 400 m / 800 m / 1500 m) carry no turn increment between SCY and LCM: the factor already absorbs it. Between SCM and LCM the increment is fixed at 6.40 s (400), 12.80 s (800) and 24.00 s (1500).
Not applied here: altitude adjustment. Some timing systems add an altitude correction for distance events swum above roughly 300 m elevation. If your governing body requires one, apply it separately.
Exact distance conversions
One yard is exactly 0.9144 m. Nothing about this is an estimate — only the time conversion is.
| Yards | Metres | Metres | Yards |
|---|---|---|---|
| 25 y | 22.86 | 25 m | 27.34 |
| 50 y | 45.72 | 50 m | 54.68 |
| 100 y | 91.44 | 100 m | 109.36 |
| 200 y | 182.88 | 200 m | 218.72 |
| 500 y | 457.20 | 400 m | 437.45 |
| 1000 y | 914.40 | 750 m | 820.21 |
| 1650 y | 1508.76 | 1500 m | 1640.42 |
| 1760 y (1 mile) | 1609.34 | 1609.34 m (1 mile) | 1760.00 |
Neither the 1650-yard nor the 1500-metre freestyle is a mile. Both are shorter.
The single most common error
Reading a 25-metre time as a 25-yard time (or the reverse) is the mistake that produces impossible entry times. The pools look the same. They are not.
| If the time was swum in… | Its LCM equivalent |
|---|---|
| Enter a confirmed short-course time to populate this table. | |
A 25 m lap is 2.14 m longer than a 25 y lap — 8.6% more water per length, and no extra wall to help you.
Method
This tool implements the course-conversion model used by the timing and team-management software that clubs actually run (Hy-Tek / Colorado Timing lineage): the time is multiplied by a distance factor, then a per-wall increment is added when walls are lost or subtracted when walls are gained. Times are handled internally in hundredths of a second and rounded once, at the end.
Both directions are computed from the same constants, so converting a time out and back returns the original within one hundredth. That round trip is displayed as the independent check.
Sources
- Course conversion factors and per-stroke increments — SportsEngine Motion: How to perform course conversion / factoring of times
- Converted times are not official times — USA Swimming, Times and Recognition Policy Manual (PDF)
- Official results and time standards — USA Swimming Times
- Pool dimensions and course definitions — World Aquatics Competition Regulations and World Aquatics swimming rules
- Contribution of starts and turns to race time; short-course races average several per cent faster than the same long-course event — Born et al., section analyses of short-course individual medley (PMC9157519) and Born et al., turn performance in top-elite swimmers (PMC8472918)
Limits
- Conversion factors are population averages. A swimmer with an exceptional underwater kick loses more than average when walls are removed; a distance freestyler may lose almost nothing.
- Governing bodies use different tables. The NCAA, World Aquatics points and individual LSCs may not produce the figure shown here.
- The 100 individual medley does not exist as a long-course event, and the 50 m stroke events are not part of every championship programme. The tool stops rather than inventing a conversion.
- No altitude correction is applied.
Last reviewed: July 2026 · Next review due: July 2027 · Published by clinicaltoolslibrary.com
Full disclaimer, scope and how to report an error
This calculator is an educational reference and decision aid published by clinicaltoolslibrary.com. It is not medical advice, coaching advice, or an official timing service, and it does not tell you whether to train, compete, or enter a meet. Its output depends entirely on the values you enter; a wrong course or distance produces a confidently wrong answer.
Converted times have no official standing. Under USA Swimming's Times and Recognition Policy Manual, a time ceases to be official once it is converted from one course to another. Records, rankings, time standards and qualification are always assessed in the course actually swum. Meet hosts may accept converted times for entry and seeding at their discretion — read the meet information sheet.
Swimming carries physical risk. Nothing here should be used to justify training or racing against medical advice. If you have a health condition affecting exercise tolerance, speak to your clinician.
Found an error? Report calculation or reference errors to clinicaltoolslibrary.com via the site contact page so the figure can be checked against source and corrected. Errors in a medical device or a medicine — not in this tool — should be reported to your national regulator: in the United States, the FDA's MedWatch programme; in the United Kingdom, the MHRA Yellow Card scheme; in the EU, your national competent authority.
Printed from clinicaltoolslibrary.com — Swim Time Converter. Verify all figures against current source material before use.
Last reviewed July 2026 · Educational reference · A converted time is an estimate, never an official result.
