Pool Square Footage Calculator
Calculate pool surface area for liner replacement, cover sizing, or chemical dosing. Different pool shapes use different formulas.
Pool Area Calculator
Pool shape formulas
Rectangular pool: length × width. A 16 × 32 ft pool has a 512 sq ft surface area.
Round pool: π × radius². A 24-ft round pool has radius 12 ft, area = 3.14 × 144 = 452 sq ft.
Oval pool: rectangle (length × width) + circle (π × radius²) where the radius is half the pool width. A 15 × 30 ft oval = (15 × 15 rectangle) + (3.14 × 7.5²) = 225 + 177 = 402 sq ft.
Liner vs. surface area
Surface area is the top of the water. Liner area includes the pool floor (the surface area) PLUS the walls (perimeter × wall depth). For a 16 × 32 × 4 ft pool: floor = 512 sq ft + walls (96 × 4) = 384 sq ft, total liner area ~ 896 sq ft.
Pool covers (winter or solar) match the surface area plus a few feet of overhang. Order a cover sized for the next pool size up if you want generous overlap.
Pro tips
Use diameter, not radius, when ordering
Round pools are typically advertised by diameter (24 ft, 27 ft, 30 ft). Cover and liner suppliers list by diameter, not radius. Convert to radius only for the area formula.
Free-form pools are tricky
For kidney-shaped or true free-form pools, divide into multiple rectangles and circle segments. Add 5% to your final number to account for irregular boundaries.
Chemical dosing uses gallons, not square footage
Pool chemical doses are based on water volume (gallons). Volume = length × width × average depth × 7.48. A 16 × 32 × 5 ft pool holds about 19,000 gallons.
Decking is calculated separately
Pool deck square footage is the deck area minus the pool. For a 20 × 40 ft deck around a 16 × 32 ft pool: 800 - 512 = 288 sq ft of decking.