How Many Gallons in an Olympic Pool?
An Olympic pool is 50 m × 25 m, and with the 2.5 m minimum depth in the current World Aquatics rules it holds at least 3,125 cubic meters, about 825,500 US gallons. The often-quoted 660,000 gallons (2,500 m³) comes from a shallower 2.0 m depth.
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On this page (7 sections)
Both numbers are right for their depth, so the useful answer is a short formula you can reuse for any pool. The rest of this page shows the math, then puts other pool sizes next to a backyard pool.
The size of an Olympic pool
World Aquatics (the sport's governing body, formerly FINA) sets the dimensions in its swimming pool certification rules, in force from 1 January 2024. For the Olympic Games and the World Aquatics Championships, a 50 m pool must be at least 25.00 m wide if permanent, and at least 2.5 m deep. If the same pool is used for artistic swimming as well as swimming, the minimum depth is 3 m. The World Aquatics Championships 25 m pool needs at least 2.0 m, with 2.5 m preferred.
The length is 50 m between the touch panels, and the rules allow a few centimeters of tolerance on the walls. We ignore that here, because 2 or 3 centimeters change the answer by well under 0.1%.
The math: from meters to gallons
- Volume in cubic meters = length × width × depth. For the minimum Olympic pool: 50 × 25 × 2.5 = 3,125 m³.
- Liters = cubic meters × 1,000. That is 3,125,000 L.
- US gallons = liters ÷ 3.785411784, because a US gallon is exactly that many liters. That is about 825,538 gallons.
Run the same steps with a depth of 2.0 m: 50 × 25 × 2.0 = 2,500 m³ = 2,500,000 L = about 660,430 gallons. That is where the common "660,000 gallons" figure comes from. At 3 m, the multi-sport minimum, the volume is 3,750 m³, about 990,645 gallons.
A cubic meter of water weighs about one metric ton, so the minimum Olympic pool holds roughly 3,125 metric tons of water.
Olympic pool next to other pools
Only the first three rows come from World Aquatics rules. For the other rows, the dimensions are our own examples, so you can see the scale. Use your own numbers in the pool volume calculator.
| Pool | Dimensions | Gallons | Olympic pool = how many? |
|---|---|---|---|
| Olympic, 2.5 m minimum depth | 50 m × 25 m × 2.5 m | 825,538 | 1 |
| Olympic, 2.0 m depth (older and common figure) | 50 m × 25 m × 2.0 m | 660,430 | 0.8 |
| Olympic, 3.0 m depth (multi-sport minimum) | 50 m × 25 m × 3.0 m | 990,645 | 1.2 |
| 25 m pool (our example) | 25 m × 15 m × 2.0 m | 198,129 | 4.2 fit in the 2.5 m Olympic |
| 25 yard pool (our example) | 75 ft × 42 ft × 4.5 ft average | 106,036 | 7.8 fit |
| Backyard 16 × 32 pool (our example) | 16 ft × 32 ft × 5 ft average | 19,150 | 43 fit |
| Home lap pool (our example) | 40 ft × 8 ft × 4 ft average | 9,575 | 86 fit |
| 24 ft round above-ground pool (Intex Ultra XTR 24 × 52) | factory capacity | 12,481 | 66 fit |
In the last column, the Olympic volume is the 2.5 m minimum (825,538 gallons) divided by each pool's gallons. Using the 2.0 m volume, about 53 of the 24 ft pools would fit. See the 24 ft round pool page for that model. The 16 × 32 row matches the 16 × 32 pool page, though it uses a 5 ft average depth that you should replace with your own.
What a pool this size means for chemicals
You will not dose an Olympic pool with a measuring cup. Large pools are run with automatic feeders and daily testing by trained staff. For a backyard pool, the principle is the same and the scale is not. Use the volume of your own pool, find the nearest dose sheet, and scale to your volume. The pool fill cost calculator shows what it costs to fill a pool of your size. At 825,538 gallons, the water alone would be a very large bill, which is one reason big pools are rarely drained.
Common mistakes with the numbers
- Mixing up yards and meters. A 25 yard pool is not a 25 m pool. A yard is 0.9144 m, so a 25 yard pool is about 8.6% shorter.
- Using the deepest point as the average depth. Most pools slope. For a pool with a shallow and a deep end, use the average depth in the volume formula.
- Copying a liters number as gallons. 3,125,000 L is not 3,125,000 gallons. Divide by 3.785 to convert liters to US gallons.
- Using UK gallons. A UK (imperial) gallon is bigger than a US gallon, so a figure in imperial gallons will be too high if read as US gallons. All numbers here are US gallons.
For standard home pool sizes in one list, see the pool gallons chart.
FAQ
How many gallons are in an Olympic pool?
About 825,538 US gallons at the 2.5 m minimum depth in the current World Aquatics rules (3,125 m³). About 660,430 gallons at 2.0 m depth, which is the figure many sites still quote.
How many liters are in an Olympic pool?
At least 3,125,000 L at 2.5 m depth, or 2,500,000 L at 2.0 m. A deeper pool holds more.
How many gallons are in a junior Olympic pool?
We could not confirm one official definition of a "junior Olympic" pool, and it varies by source. Use the length, width and average depth of the pool you mean, and apply the formula above.
How many gallons are in a 25 meter pool?
It depends on width and depth. Our example of 25 m × 15 m × 2.0 m holds about 198,129 gallons. The World Aquatics Championships 25 m pool needs a depth of at least 2.0 m.
How many gallons are in a typical backyard pool?
Our example 16 × 32 pool at an average 5 ft depth holds about 19,150 gallons. Yours will differ with its size and depth. The pool gallons chart lists common sizes.
Sources
- World Aquatics, Swimming Pool Certification (in force from 1 January 2024), sections on width and water depth, read 2026-10-06: resources.fina.org
- NIST, conversion factors for the US gallon (3.785411784 L; we did not open this page on 2026-10-06): nist.gov
- Intex Ultra XTR Frame 24 ft × 52 in (12,481 gallons), read 2026-09-29: intexcorp.com
- Volume formulas and gallon constants: methodology