Pool Volume Calculator — Litres

How to Calculate Pool Volume in Litres

Multiply the pool's cubic-metre volume by 1,000 to convert to litres, or multiply cubic feet by 28.3168. The metric path (metres → cubic metres × 1,000) produces an exact result with no rounding error. The imperial path (feet → cubic feet × 28.3168) uses the internationally accepted conversion factor between cubic feet and litres. A third option — US gallons × 3.78541 — converts an existing gallon figure into litres directly.

Average depth matters more than wall height. A pool with a 1 m shallow end and a 2.5 m deep end has an average depth of 1.75 m — not the 2.5 m a homeowner might assume from the diving area. Using 2.5 m instead of 1.75 m overestimates volume by 43%, which throws off every chemical dose for the season.

Measure water depth with a weighted string dropped from the pool edge to the bottom at 3 points: the shallow end, the centre, and the deep end. Add the 3 readings and divide by 3 to get the average. For flat-bottom above-ground pools, a single depth measurement is enough.

Australian, UK, New Zealand, European, and Canadian chemical labels dose per 1,000 litres of water. Matching your pool volume to the label unit removes conversion errors at the point of dosing.

Australian pool chemical labels state dose per 1,000 L — divide your pool's litre volume by 1,000 to find the number of dose units required.

What Makes Litres the International Standard for Pool Volume

Litres are the standard unit for pool volume in Australia, the United Kingdom, New Zealand, the European Union, and Canada. Chemical labels, pump flow rates, and filter sizing in these markets all reference litres. Choosing the wrong volume unit at measurement time introduces a multiplied error into every chemical dose applied to the pool.

The metric system replaced imperial measurement in Australian law in 1970, in the UK and New Zealand in 1972, and across the European Union over the following decade. Pool equipment sold in these markets — pumps, filters, chlorinators — rates flow and capacity in litres per minute (L/min) or litres per hour (L/h), not gallons per minute. Using litres from the start avoids an extra conversion step between the volume result and the equipment specification.

1 m³ = 1,000 L exactly — no rounding error when working in metric. Australian labels dose per 1,000 L. UK labels dose per 1,000 L or 10,000 L depending on the brand and product concentration.

Pool owners in the US who need gallon-based results can use the pool volume calculator in gallons for US gallon formulas and reference tables.

Pool Volume in Litres — Common Sizes Reference

The table below lists 8 residential pool sizes with pre-calculated volumes. Litres lead in the results column; cubic metres and US gallons follow for cross-reference.

Calculated using shape formula. Litres = cu ft × 28.3168 or m³ × 1,000. US Gal = Litres ÷ 3.78541.

Metric pool sizes range from 14,249 litres (3,764 US gallons) for a small 3.6 m round pool to 115,200 litres (30,432 US gallons) for a 6 × 12 m rectangular pool. Imperial-sized pools in the table fall between 64,211 litres (16,965 US gallons) and 89,672 litres (23,691 US gallons).

The imperial-sized entries (16 × 32 ft, 18 × 36 ft, 24 ft diameter) are included for pool owners in countries that built pools before metrication — these dimensions remain common in older Australian and Canadian installations. For custom sizes not listed here, use the pool volume by size lookup or enter your dimensions into the homepage calculator.

How to Calculate Pool Volume by Shape in Litres

Two paths produce litres: the metric path multiplies cubic metres by 1,000, and the imperial path multiplies cubic feet by 28.3168. The metric path is shorter and produces an exact result because 1 m³ = 1,000 L by definition. The imperial path requires the 28.3168 conversion factor, which introduces minor rounding past the fifth decimal — negligible for chemical dosing but worth noting for engineering specifications.

Walk through a complete metric calculation for a 16 × 32 ft pool converted to metres (4.88 m × 9.75 m) with a 1.68 m average depth.

Result: 79,930 litres (21,115 US gallons).

Taking the imperial path for the same pool: 16 × 32 × 5.5 = 2,816 cu ft, then 2,816 × 28.3168 = 79,748 litres. The 182-litre difference between the two paths comes from rounding the foot-to-metre conversions — both results fall within 0.3% of each other, well inside the tolerance for residential pool dosing.

Round pools follow the same 4-step process but replace Step 1 with D² × 0.7854. A 4.5 m round pool: 4.5² × 0.7854 = 15.90 m², then 15.90 × 1.35 = 21.47 m³, then 21.47 × 1,000 = 21,470 litres (5,671 US gallons). Use the round pool volume calculator for instant results. Rectangular pool calculations skip the 0.7854 step since there is no curve to account for.

For detailed breakdowns of every shape formula, see pool volume formulas for all shapes. To calculate chemical doses based on your result, use the pool chemical dosing guide.