Training & Development

Short course vs long course times: compare them fairly

Short course vs long course times differ because a 25-metre pool gives swimmers more turns and push-offs. Compare the same course; conversions add context, but FPN checks a qualifying time against the table for the pool it was swum in, never a converted one.

September 18, 2026 · 4 min read

Idea in Brief

  • Pool length changes the clock. More walls usually make a 25-metre swim faster than the same event in 50 metres.
  • Compare the same course. A December best can make a solid July swim look worse than it is.
  • Conversion is an estimate. It helps with context and planning, but a TAC is only ever checked against the table for the pool the swim was in.

The December result is open on your phone while July’s time appears on the board. July is slower, and a good season suddenly looks doubtful. Before judging either swim, check the course beside it. Piscina curta (25-metre pool) and piscina longa (50-metre pool) produce different clocks. Portuguese swimming keeps separate sets of times because the same number doesn’t mean the same swim across both courses. Comparing a short-course best with a long-course race can make a normal pool effect look like a lost season.

The Portuguese season generally opens short course in autumn. It then moves to the 50-metre pool for the championships that close it. Last season showed that broad pattern. In the site’s database, 80 of the 81 Portuguese meets held in October and November 2025 were short course. The December championships and zonal meets were short course too. The national championships in March and July were long course. It isn’t a fixed rule for each meet, so read the course label. The Federação Portuguesa de Natação (FPN) qualifying annex makes the same split, with one table for piscina curta and one for piscina longa.

A 25-metre pool gives a swimmer twice as many walls to push off as a 50-metre pool. In a 100 m race, that means three turns in short course and one in long course. From the stands, you see the swimmer reach a wall more often. Each turn brings another push and a stretch underwater before surface swimming starts again. A push-off is faster than swimming. Across age-group swims, the gap is usually one to two seconds per 100 m. How much a swimmer gains varies with their turns and underwater work.

For a fair comparison, use the swim time converter. Pick the stroke and the distance, say which pool the swim happened in, and type the time. The site’s worked example turns 1:10.00 over 100 m freestyle in a 25-metre pool into 1:11.60 in a 50-metre pool. The result adds an allowance for the missing turns. It’s a well-informed estimate built around average turns, so coaches can use it for planning and comparison. A swimmer with strong underwater work may beat it. A swimmer still learning turns may come in behind it.

Qualifying times have a harder boundary. The FPN TAC page lists each mínimo (qualifying time) by event, escalão, gender and pool type. It covers zonal tournaments and national championships. For championship access, the FPN checks each time against the table for the pool it was swum in: a 25-metre time against the short-course table, a 50-metre time against the long-course table. Either can earn entry, but a converted time never counts. Other meets may accept converted entry times, but the meet announcement or coach has the final answer. Check the course before reading July as a setback. Then check the TAC column before treating any converted time as a mínimo.

Share it with your swimmer

Keep the explanation tied to the pool they raced in:

  • Under 12 (you’re driving). “That pool has more walls, so faster can be normal.” This makes the course difference easy to see.
  • 12–15 (sharing the wheel). “Let’s compare July with another 50-metre swim.” It gives the result fair context.
  • 16+ (they’re driving). “The converter estimates the other course, but the TAC decides whether the time counts.” This separates planning from entry.

Stay aligned with your coach

The coach handles race analysis, entries and which TAC applies. You can keep course labels attached to times at home. Ask, “Should we compare this with their long-course best or use a converted estimate?” Then leave the entry decision with the coach.

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