Pool Gallons Calculator – Estimate Pool Water Volume

Calculate how many gallons of water your pool holds. Supports rectangular, circular, and oval pool shapes. Enter dimensions for instant results.

Pool Gallons Calculator Formula

Rectangular: L x W x D x 7.48; Circular: π x (D/2)² x D x 7.48; Oval: π x (L/2) x (W/2) x D x 7.48

How to Calculate Pool Gallons

  1. 1. Measure the pool dimensions in feet (length, width, diameter, depth)
  2. 2. For rectangular pools: Volume (cu ft) = Length x Width x Depth
  3. 3. For circular pools: Volume (cu ft) = π x (Diameter/2)² x Depth
  4. 4. For oval pools: Volume (cu ft) = π x (Long Diameter/2) x (Short Diameter/2) x Depth
  5. 5. Convert to gallons: Gallons = Volume (cu ft) x 7.48

Example Calculation

Let's say you're filling a 24ft round above-ground pool with 4ft average depth.

  • shape: circular
  • diameter: 24
  • depth: 4

The pool holds approximately 13,526 gallons of water

Tips

  • Use the average depth if your pool has a shallow and deep end — measure both and divide by 2
  • One cubic foot of water contains 7.48 gallons
  • A standard garden hose flows at about 8-12 gallons per minute, so filling a 13,000 gallon pool takes roughly 18-27 hours
  • For irregular pool shapes, break the pool into sections and calculate each separately, then add them together
  • Knowing your pool's gallon capacity is essential for proper chemical treatment and filter sizing

Frequently Asked Questions

How many gallons in a 24ft round pool?
A 24-foot round pool with a 4-foot average depth holds approximately 13,526 gallons. At 3 feet deep it holds about 10,145 gallons, and at 4.5 feet deep it holds about 15,218 gallons.
How many gallons in a 15x30 pool?
A 15x30 rectangular pool with a 4-foot average depth holds approximately 13,464 gallons. This is calculated as 15 x 30 x 4 x 7.48 = 13,464 gallons.
What is the average gallons in an inground pool?
An average inground pool holds between 15,000 and 20,000 gallons. Small pools may hold 10,000-15,000 gallons, while large pools can hold 25,000+ gallons.

Related Calculators