Skip to content

Pool Volume Calculator

Calculate how many gallons of water your swimming pool holds. Supports rectangular, circular, oval, and oblong shapes with variable depth.

Pool Volume Worksheet

Something wrong or missing? Tell us — we read every report and fix issues fast.

How to Calculate Pool Volume

Select your pool shape, enter the dimensions in feet, and the calculator determines the volume in gallons, liters, and cubic feet. If your pool has a shallow and deep end, enter both depths for an accurate average.

Pool Volume Formulas

Rectangular Pool

Volume = Length × Width × Average Depth

The most common pool shape. Multiply all three dimensions to get cubic feet, then multiply by 7.48 for gallons.

Circular Pool

Volume = π × (Diameter ÷ 2)² × Average Depth

Common for above-ground pools. Measure the diameter across the widest point.

Oval Pool

Volume = π × (Length ÷ 2) × (Width ÷ 2) × Average Depth

Uses the ellipse area formula. Measure the longest and widest dimensions.

Oblong Pool (Stadium Shape)

Volume = (Rectangle area + Circle area) × Average Depth

A rectangle with semicircular ends. The calculator computes the rectangular center section plus the two semicircles that form a full circle.

Average Depth

Most pools slope from shallow to deep. The average depth is simply:

Average Depth = (Shallow Depth + Deep Depth) ÷ 2

For flat-bottom pools, just enter the single depth value.

Unit Conversions

  • 1 cubic foot = 7.48052 US gallons
  • 1 cubic foot = 28.3168 liters
  • 1 US gallon = 3.78541 liters

Why Pool Volume Matters

  • Chemical dosing: Chlorine, pH, alkalinity, and stabilizer amounts are based on water volume
  • Equipment sizing: Pumps and filters are rated for specific pool volumes
  • Fill time: A garden hose at ~9 GPM fills about 540 gallons per hour
  • Water cost: Multiply volume by your local water rate per gallon
  • Heater sizing: BTU requirements depend on water volume and desired temperature rise

Common Pool Sizes

  • 12 ft round above-ground: ~3,400 gallons (4 ft depth)
  • 15 ft round above-ground: ~5,300 gallons (4 ft depth)
  • 24 ft round above-ground: ~13,500 gallons (4 ft depth)
  • 12 × 24 ft in-ground: ~8,600 gallons (3–6 ft depth)
  • 16 × 32 ft in-ground: ~19,200 gallons (3.5–8 ft depth)
  • 20 × 40 ft in-ground: ~30,000 gallons (3.5–8 ft depth)

Related Calculators

Slope Percentage Calculator — % Grade, Angle, Ratio Calculate slope percentage from rise and run, or convert between percent grade, degrees, and 1:N ratio. Includes ADA ramp, driveway, road, and drainage standards. Acreage Calculator — Land Area in Acres, Hectares Calculate land area in acres from length and width. Converts to sq ft, hectares, sq m, and more. Square Yards Calculator — Carpet, Flooring, Cost Calculate square yardage from length and width. Includes unit conversion and optional cost estimation for carpet and flooring. Square Footage Calculator — Room Area + Paint Estimate Calculate square footage for rooms and spaces. Get paint and flooring estimates from one entry. Paint Calculator — Coats, Doors, Windows, Cost Calculate paint and primer needed with custom door/window dimensions, ceiling toggle, and cost estimates. Flooring Calculator — Multi-Room with Pattern Waste Calculate flooring for multiple rooms with waste presets by pattern (straight/diagonal/herringbone) and box/carton calculator.

Frequently Asked Questions

How do I calculate pool volume in gallons?

Multiply length by width by average depth in feet to get cubic feet, then multiply by 7.48 to get gallons. Average depth is the shallow end depth plus the deep end depth, divided by 2. For a flat-bottom pool, use the single depth. Pool volume sets chemical dosages, pump and filter sizing, and fill time.

How many gallons does a 16 x 32 pool hold?

A 16 by 32 ft rectangular pool with an average depth of 5 ft holds about 19,150 gallons (16 x 32 x 5 x 7.48). A shallower average depth reduces that figure proportionally, so the same pool at 4 ft average depth holds about 15,300 gallons. Step ledges displace water, so subtract their volume for a precise figure.

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

A standard garden hose delivers about 9 gallons per minute, so a 15,000 gallon pool takes roughly 28 hours to fill. Divide the pool volume in gallons by the hose flow rate to get minutes, then divide by 60 for hours. A larger pool or lower water pressure can stretch the fill to several days.

How do I calculate the volume of an oval pool?

Oval pool volume in gallons is pi x (length / 2) x (width / 2) x average depth x 7.48. Measure the longest dimension as length and the widest as width. A 15 by 30 ft oval pool with a 4 ft average depth holds about 10,575 gallons. An oval holds about 21% less water than a rectangle of the same size.