Swimming workouts are usually written by distance. Before starting one, you need to know how long your pool is and whether it is measured in yards or meters.
Common lap-pool lengths are 25 yards, 25 meters, and 50 meters.
A length is one trip from one end of the pool to the other.
The word lap is less useful because people use it differently. Some swimmers mean one length. Others mean down and back.
For that reason, these workouts use distance and lengths rather than laps.
In a 25-yard pool:
25 yards = 1 length
50 yards = 2 lengths
100 yards = 4 lengths
200 yards = 8 lengths
If a workout says 100 yards, swim four lengths of a 25-yard pool.
A 25-yard pool is common in the United States and is usually called a short-course yards or SCY pool.
In a 25-yard pool:
25 yards = 1 length
50 yards = 2 lengths
100 yards = 4 lengths
200 yards = 8 lengths
500 yards = 20 lengths
1,000 yards = 40 lengths
The workouts on this site are written in yards, so a 25-yard pool matches the listed distances exactly.
A 25-meter pool is called a short-course meters or SCM pool. These are common in Canada and other countries that use the metric system.
The counting works the same way as in a 25-yard pool:
25 meters = 1 length
50 meters = 2 lengths
100 meters = 4 lengths
200 meters = 8 lengths
If you are using one of the yard-based workouts on this site, you can usually just substitute meters for yards. If the workout says 25 yards, swim 25 meters.
In practice, swim 50 yards = swim 50 metres.
The workout will be about 9 percent longer overall, but for recreational swimming there is usually no need to calculate an exact conversion.
A 50-meter pool is called a long-course meters or LCM pool. This is the pool length used for Olympic swimming.
In a 50-meter pool:
50 meters = 1 length
100 meters = 2 lengths
200 meters = 4 lengths
400 meters = 8 lengths
800 meters = 16 lengths
1,500 meters = 30 lengths
Long-course swimming involves fewer turns and push-offs than swimming the same distance in a 25-meter pool, so the same distance can feel different.
One yard equals 0.9144 meters. A 25-meter pool is therefore about 9 percent longer than a 25-yard pool.
For most recreational workouts, you do not need to convert every distance exactly. If a workout calls for 4 × 50 yards and you are swimming in a 25-meter pool, you can usually swim 4 × 50 meters instead.
Your total distance will be slightly longer, but the workout structure stays the same.
If you are already near the limit of what you can comfortably complete, shorten the workout if needed.
The workouts on this site are listed in yards because they are designed around a 25-yard pool.
In a 25-meter pool, the easiest approach is usually to keep the same structure and substitute meters for yards.
If the workout says 4 × 50 yards, swim 4 × 50 meters.
If it says 4 × 100 yards, swim 4 × 100 meters.
A 1,500-yard workout done this way becomes a 1,500-meter workout, so the total distance is about 9 percent longer.
You do not need to calculate exact conversions at the pool unless you want to.
Most distances of 50 or more are easy to adapt. A 50 is one length, a 100 is two lengths, and a 200 is four lengths.
Sets built around 25-yard repeats cannot be reproduced exactly in a 50-meter pool. In most cases, use 50-meter repeats and keep the purpose and effort of the original set in mind.
The total distance does not need to match perfectly.
Swimming workouts commonly use a number followed by a distance.
4 × 50 means swim 50 four times.
If you are in a 25-yard pool, each 50 is two lengths. Swim the two lengths, take the listed rest, and then start the next 50.
4 × 50 = 200 total yards.
Likewise:
4 × 25 = 100 yards
4 × 100 = 400 yards
3 × 200 = 600 yards
The first number tells you how many repeats to do. The second tells you the distance of each repeat.
A workout that says 200 easy freestyle usually means swim 200 continuously.
A workout that says 4 × 50 easy freestyle covers the same total distance, but it is divided into four separate swims with rest between them.
Follow the repeats as written rather than combining everything into one continuous swim.
Do not try to judge the pool length by looking at it. Ask the lifeguard or front desk, check the pool signage, or look at the facility information online.
Once you know whether your pool is 25 yards, 25 meters, or 50 meters, the workout distances are simple to follow.
A true mile is 1,760 yards, or about 1,609 meters.
Swimming also has a race commonly called the mile. In a 25-yard competition pool, that race is 1,650 yards. In meter competition, the comparable long-distance event is 1,500 meters.
Because the term can mean different distances, use the stated yard or meter distance when following a workout rather than relying on the word mile.
A length is one trip from one end of the pool to the other. The word lap can mean different things, so these workouts use lengths and distance instead.
A 25-yard pool is 25 yards per length. A 25-meter pool is 25 meters per length. A 50-meter pool is 50 meters per length.
The workouts on this site are written in yards. If you swim in a 25-meter pool, using the same numbers in meters is usually the simplest option. Your total distance will be about 9 percent longer.
Once you know your pool length, the rest is just counting lengths.