Pool Volume Calculator

Calculate how many gallons a rectangular, round, or oval pool holds.

⏱ Updated: 18 Sep 2026

Calculator

Free pool volume calculator: find how many gallons a rectangular, round, or oval pool holds.

Gallons
Cubic Feet
Liters

Uses the average of the shallow- and deep-end depths as a constant depth across the whole floor — real sloped-floor pools vary slightly from this, but it's the standard estimating method pool suppliers use.

Choose a pool shape, then enter its dimensions and depths to calculate volume in gallons, cubic feet, and liters.

How to Use the Pool Volume Calculator

Pick a shape first — Rectangular, Round, or Oval — since that determines which dimension fields appear; every shape also asks for a shallow-end and deep-end depth, even a round pool with a sloped floor.

A pool with a sloped floor doesn't have one depth, so the standard estimating approach — the one this calculator uses — averages the shallow and deep ends into a single flat depth and runs the volume formula on that.

average depth = (shallow depth + deep depth) ÷ 2
Rectangular: volume = length × width × average depth
Round:       volume = π × (diameter ÷ 2)² × average depth
Oval:        volume = π × (length ÷ 2) × (width ÷ 2) × average depth

It's an approximation, not an exact integral of a curved floor, but it's close enough for the two things pool owners actually need volume for: dosing chemicals correctly and sizing a pump or filter to the right turnover rate. A pool with an unusually complex floor shape — multiple depth transitions, a built-in bench, a tanning ledge — will read a bit differently on a tape measure than what this tool assumes, and the gap grows with how far the real shape drifts from a simple sloped rectangle, circle, or oval.