Why are short-course times faster?

A 25m pool has twice as many turns per distance as a 50m pool, and a good push-off underwater is faster than swimming on the surface. Those extra turns make short-course times measurably quicker, which is why a conversion is needed to compare fairly.

How much faster is short course?

The gap depends on stroke and distance. Sprints gain proportionally more from turns, and breaststroke and butterfly benefit most because their underwater phases are efficient. Typical differences range from roughly 1% for a 50m freestyle to 3% or more for distance and form-stroke events.

Is this exactly the FINA points conversion?

No single percentage matches FINA's full points system, which uses base times per event. This tool uses event-specific percentage adjustments calibrated to the typical short-course advantage, so it is a close practical estimate rather than an official points conversion.

Which direction does it convert?

Both. Tell the tool whether your time was swum in a 25m or 50m pool and it converts to the other. Converting short course to long course adds time (removes the turn advantage); long to short removes time.

Can I use this for yards pools?

This calculator handles metric 25m and 50m courses only. A 25-yard pool is shorter than 25 metres, so yard times need a separate distance-based conversion before any course adjustment, which this tool does not perform.

Swimming Short-Course to Long-Course Converter

Email me this result

Get this tool's output sent to your inbox, plus one useful tool a week. No spam, unsubscribe any time.

Compare 25m and 50m times fairly

A time swum in a 25m pool is not directly comparable to one swum in a 50m pool, because the shorter course gives you twice as many fast turns. To rank a swim or set a realistic target you must convert between short course (SCM) and long course (LCM). This tool applies an event-specific adjustment so you can move a time from one course to the other.

How it works

Short course is faster by a percentage that depends on stroke and distance — more turns and more efficient underwater phases mean a bigger advantage. The tool stores a turn-advantage percentage per event, then:

long_course_time  = short_course_time * (1 + advantage)
short_course_time = long_course_time  / (1 + advantage)

Sample advantages used (fraction of total time gained in short course):

50m freestyle ≈ 1.0%, 100m free ≈ 1.6%, 200m free ≈ 2.0%
Backstroke and butterfly carry slightly larger underwater advantages
Breaststroke benefits most from the legal pull-down off each wall

Enter your time, pick the event, choose which course you swam, and the equivalent in the other course is shown.

Example and tips

A 100m freestyle of 54.20 in a 25m pool, with a 1.6% advantage, converts to long course as 54.20 × 1.016 ≈ 55.07. Going the other way, a 55.07 long-course time becomes 55.07 / 1.016 ≈ 54.20 short course. Treat the result as a planning estimate: an individual swimmer’s turn quality can move the real gap by several tenths, so verify against your own season-best comparisons where you have both course times.