BCBetter Calculators

Swimming Pool Volume Calculator

Calculate the water volume of a rectangular swimming pool in gallons and liters.

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Enter your values and click Calculate

How It Works

The calculator first multiplies the pool's length, width, and average depth together to produce the total volume in cubic feet (length × width × depth = ft³). This works because a rectangular pool is a rectangular prism, and volume of a rectangular prism is simply the product of its three dimensions. The cubic foot result is then converted to US gallons by multiplying by 7.48052 — the number of gallons in one cubic foot. The same cubic foot value is also multiplied by 28.3168 to produce the equivalent in liters, since one cubic foot equals 28.3168 liters. For pools with a sloped bottom (shallow end and deep end), use the average depth, calculated as (shallow depth + deep depth) ÷ 2, to get an accurate volume estimate.

Examples

Average Backyard Pool
30 ft × 15 ft pool, 5 ft average depth.
Result: Approximately 16,831 gallons (63,713 liters).
Small Plunge Pool
12 ft × 8 ft pool, 4 ft deep.
Result: Approximately 2,874 gallons (10,876 liters).
Large In-Ground Pool
40 ft × 20 ft pool, 5.5 ft average depth.
Result: Approximately 32,904 gallons (124,554 liters).

Frequently Asked Questions

How do I calculate average depth for a sloped pool?
Add the shallow end depth and deep end depth, then divide by 2. e.g. 3 ft shallow + 8 ft deep = 5.5 ft average.
Why do I need to know my pool volume?
Pool chemical dosing (chlorine, pH adjusters) is always based on total gallons. Over- or under-dosing leads to unsafe water.
Does this work for oval or round pools?
For round pools, use diameter × diameter × depth × 5.9. For oval pools: length × width × depth × 5.9.

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