Pool Volume Calculator

How much water a pool or hot tub holds: rectangle, round, oval or kidney, shallow and deep ends, in gallons, litres and cubic metres.

A pool's volume is its surface area times its average depth. For a rectangle that's length × width × (shallow + deep) ÷ 2: a 32 × 16 ft pool from 3½ to 8 ft deep averages 5¾ ft, which is 2,944 ft³, or about 22,000 US gallons at 7.48 gallons per cubic foot. Round pools use π × radius², ovals π × half the length × half the width, and kidney pools the trade's estimate of 0.45 × the sum of the two widths × the length. In metric, an 8 × 4 m pool from 1.1 to 1.8 m deep holds 46,400 litres. Enter your pool, and a fill rate if you want the fill time, and the calculator gives the gallons, litres and the weight of the water.

Units
ft
ft
ft
ft
US gallons
22,023

83,365 litres

Cubic feet
2,944

83.36 m³

Water weight
91.9 tons

183,788 lb

Average depth
5.75 ft

shallow and deep ends

How it was worked out
  1. Average depth: (3.5 + 8) ÷ 2 = 5.75 ft
  2. 32 × 16 ft × 5.75 ft = 2,944 ft³
  3. 2,944 ft³ × 7.48 gallons per ft³ = 22,023 US gallons

For water level, measure depth to the water line rather than the top of the wall. Kidney and freeform pools use the pool trade's rule of thumb, so treat them as estimates. Chemical doses are based on volume: follow the product label.

Common use cases

  • Work out chemical doses, which are based on volume
  • Size a pump, filter or heater
  • Estimate how long a pool takes to fill
  • Check a hot tub or plunge pool's volume

How to use

  1. Choose your units and the pool's shape.
  2. Enter the length (or diameter) and width, and the depth at the shallow and deep ends.
  3. Optionally enter the fill rate of your hose or water supply.
  4. Read the gallons or litres, cubic feet or metres, water weight and fill time.

FAQ

How many gallons are in my pool?

Multiply length × width × average depth in feet, then by 7.48. A 32 × 16 ft pool averaging 5¾ ft deep holds about 22,000 US gallons. In metric, multiply in metres and by 1,000 for litres.

How do I measure a pool with a sloping floor?

Measure the depth at the shallow end and the deep end, to the water line, and use their average. Pools with a long flat shallow section and a short deep area hold less than the simple average suggests.

How heavy is the water in a pool?

A US gallon of water weighs about 8.34 lb and a litre about 1 kg, so 22,000 gallons is around 92 tons of water.

Related tools

Results are estimates for planning and buying materials, worked out from the figures you enter and typical values (weights, coverage, sizes) that vary by product and supplier. They are not engineering, building or professional advice. Check your local building code, the product maker's instructions and your supplier's figures before you buy or build, and use a qualified professional for structural, electrical and gas work.