Pool Volume Calculator

Pool Volume Calculator

How to Use the Pool Volume Calculator

1. 1

   Choose the pool shape

   Select Rectangle, Round, Oval or Kidney. Each shape shows the measurements it needs.

2. 2

   Pick feet or meters and enter the size

   Measure the inside of the pool at the water surface. Enter length and width, the diameter for a round pool, or the length and both end widths for a kidney pool.

3. 3

   Enter the water depth

   Type one depth for a flat bottom, or turn on "Sloped bottom" and enter the shallow and deep end depths. The calculator averages them.

4. 4

   Read the volume

   The result shows gallons and liters, plus cubic feet, cubic meters, surface area and average depth.

How pool volume is calculated

Volume is the water surface area multiplied by the average depth, which gives cubic feet. Each cubic foot holds 7.48 US gallons or 28.3 liters. If you enter meters, the calculator converts them to feet first, so both unit systems give the same answer.

For a sloped pool, the average depth is the shallow end plus the deep end, divided by two. This works well for a steady slope. Pools with a large flat deep area or a hopper bottom hold a bit more than the simple average suggests.

Gallons = surface area (sq ft) x average depth (ft) x 7.48

• Rectangle: length x width
• Round: 3.1416 / 4 x diameter squared (the common 5.9 x diameter² x depth shortcut uses the same geometry, rounded)
• Oval: 3.1416 / 4 x length x width, treating the pool as an ellipse
• Kidney: 0.45 x (width A + width B) x length, a widely used approximation

Worked example: a 16 x 32 ft in-ground pool

Say you have a rectangular in-ground pool that measures 16 ft by 32 ft, with water 3.5 ft deep at the shallow end and 8 ft deep at the deep end.

• Surface area: 16 x 32 = 512 sq ft
• Average depth: (3.5 + 8) / 2 = 5.75 ft
• Volume: 512 x 5.75 = 2,944 cubic feet
• Gallons: 2,944 x 7.48 = 22,021 gallons
• Liters: 2,944 x 28.3168 = 83,365 liters (about 83.4 cubic meters)
• A second example: a 24 ft round above-ground pool with 4 ft of water has 452.4 sq ft of surface and holds about 13,535 gallons (51,241 liters).

Round above-ground pool gallons by size

These figures come from the same formula as the calculator. Enter the actual water depth, which is usually a few inches below the top of the wall.

Tips for an accurate estimate

• Measure the inside of the pool, not the outside frame or coping.
• Use the water depth, not the wall height. Water normally sits partway up the skimmer opening.
• Oval above-ground pools with straight sides hold more than a true ellipse. If yours has long straight sides, run the calculator twice, once as a rectangle for the straight middle section and once as a round pool for the two curved ends together, and add the results.
• Freeform pools vary a lot. Treat the kidney result as a close estimate and adjust chemical doses using test results.
• Your water bill or a flow meter on the fill hose during a refill gives the most exact number.

Why the number matters for chemicals

Chemical labels and dosing charts are written per 10,000 gallons. If you overestimate the volume by 20%, every dose is 20% too strong, and underestimating leaves the water under-treated. Use your gallons figure in a chlorine calculator, then retest after the chemicals have circulated, and always follow the product label.

Features

• Rectangle, round, oval and kidney pool shapes
• Constant depth or shallow and deep end (average depth)
• Enter dimensions in feet or meters
• Results in US gallons, liters, cubic feet and cubic meters
• Shows surface area, average depth and the formula for the chosen shape

Frequently Asked Questions