Construction calculator

Swimming Pool Volume Calculator

Pool length (m)Pool width (m)Average water depth (m)

Pool volume (L): -

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Calculation explained

How this result was calculated

The formula, your substituted values, and the evaluated result are shown below.

Formula: length * width * averageDepth * 1000. Keep every input in the stated units. This result is a quantity-planning estimate; verify site measurements, waste factors, product yields, supplier data, applicable codes, and professional design requirements before construction.

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How the Swimming Pool Volume Calculator works

Calculate swimming pool volume for a site works construction scenario using clearly labelled project inputs.

Formula

length * width * averageDepth * 1000

Planning guidance

About this calculator

Calculate swimming pool volume for a site works construction scenario using clearly labelled project inputs.

Calculator guide

How the pool volume calculator works

For a rectangular pool, the water volume is length × width × average depth. The calculator converts cubic metres to litres by multiplying by 1,000:

Volume (L) = length (m) × width (m) × average depth (m) × 1,000

For pools with a shallow and a deep end, the average depth is roughly (shallow + deep) ÷ 2 when the floor slopes evenly.

Worked example: an 8 m × 4 m pool, 1.0 m to 1.7 m deep

Average depth: (1.0 + 1.7) ÷ 2 = 1.35 m
Volume: 8 × 4 × 1.35 × 1,000 = 43,200 L

Knowing the volume matters for chemical dosing, pump and filter sizing, heater sizing and topping-up costs.

Other shapes

Shape	Volume (m³)
Round	π × radius² × average depth
Oval	π × (length ÷ 2) × (width ÷ 2) × average depth
Kidney or freeform	about 0.85 × longest length × widest width × average depth

Multiply any of these by 1,000 for litres.

Using the volume

Pump turnover: most pools aim to filter the whole volume at least once a day. A 43,200 L pool with an 8-hour run time needs about 5,400 L/h of flow.
Chemical dosing: product labels are usually given per 10,000 L, so here you'd use 4.3 × the label dose.
Filling: 43,200 L from a garden tap at about 15 L/min takes roughly 48 hours.

Common mistakes

Using the deepest point instead of the average depth.
Measuring to the coping edge instead of the water line, which is usually 100–150 mm lower.
Ignoring steps and ledges on small plunge pools, where they make a real difference.

How many litres is my pool?

Length × width × average depth × 1,000. A 10 m × 5 m pool averaging 1.4 m holds about 70,000 L.

How do I work out average pool depth?

For an evenly sloping floor, add the shallow and deep depths and divide by 2. For a stepped floor, measure each section separately.

How long should my pool pump run?

Long enough to turn over the full volume at least once a day. Many pools run 6–8 hours in summer.

Written by Sam Alex, civil engineer. About the author