Sawhorse Calc

Pool volume calculator

Enter the pool's shape and size and the depth at each end. You get the gallons it holds, litres alongside, how long a hose takes to fill it and what the water costs.

Areas to add up

Lengths in feet. 12.5 means 12 ft 6 in. You can also type 12' 6" or 6 in.Lengths in metres.

Depth and filling

Starting figures are typical. Type the ones on your product or quote if you have them.

Cost (optional)

18,193 gallons

Average depth
4.75 ft
Cubic feet
2,432.0
Litres
68,866
Hours to fill with one hose
30.3

How to work it out

  1. Measure the length and width of the water surface, or the diameter of a round pool.
  2. Measure the water depth at the shallow end and the deep end. For an above-ground pool, measure the water, not the wall: water usually sits a few inches below the top.
  3. If the depth is the same all over, enter it in both boxes. The average assumes an even slope; if your deep end is a short, steep hopper, the real figure will be a little lower.
  4. For an oval pool, choose Known area and enter length × width × 0.785. For a kidney pool, use (widest width + narrowest width) × length × 0.45.

Quick formulas

PoolGallons
RectangleLength × width × average depth × 7.48
RoundDiameter × diameter × average depth × 5.9
OvalLength × width × average depth × 5.9
Kidney(A + B) × length × 0.45 × average depth × 7.48

These are common starting points. Your site, climate and supplier may call for something different.

A worked example

A 16 by 32 ft pool, 3.5 ft at the shallow end and 6 ft at the deep end, has an average depth of 4.75 ft. That is 16 × 32 × 4.75 = 2,432 cubic feet, and 2,432 × 7.48 = about 18,190 gallons.

Why the number matters

Chemical doses on every bottle, and the size of pump, filter, heater and salt chlorinator, are all set by gallons. Once you know yours, the pool salt calculator tells you how much salt to add.

Common questions

How many gallons are in a cubic foot of water?

7.48 US gallons. One cubic metre is 1,000 litres, or about 264 US gallons.

How many gallons is a 24 ft round pool?

At 4 ft of water, 24 × 24 × 4 × 5.9 = about 13,500 gallons. At 4.5 ft, about 15,200 gallons.

How do I work out average depth?

Add the shallow and deep end depths and divide by two. A pool 3 ft at one end and 8 ft at the other averages 5.5 ft. This assumes a fairly even slope.

How long does it take to fill a pool with a hose?

A garden hose often gives 5 to 10 gallons a minute, so an 18,000 gallon pool takes about 30 to 60 hours. Time how long your hose takes to fill a 5 gallon bucket to get your own flow.

How much does it cost to fill a pool?

Multiply the gallons by your water rate. Rates are often a few dollars to around $10 per 1,000 gallons; check your water bill. Some areas offer a pool fill discount on sewer charges.

Doing this job for a customer? Turn your numbers into a free written estimate on QuoteToPaid.

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