How it works
Pick the pool shape and enter its dimensions with the shallow and deep end water depths. The calculator uses the average depth and returns the volume in US gallons, the number you need for every chemical dose on a label.
Round pools use π × radius², ovals π ÷ 4 × length × width, and kidney pools the industry rule of 0.45 × (widest end + narrow end) × length. For above-ground pools, use the actual water depth, usually a few inches below the wall height.
The chlorine row shows how much product raises free chlorine by the amount you enter. One ppm in 10,000 gallons is about 38 grams of chlorine: 12.8 fl oz of 10% liquid, 10.2 fl oz of 12.5%, about 2 oz of 65% cal-hypo or 2.4 oz of 56% dichlor.
Formula
Gallons = surface area × (shallow + deep) ÷ 2 × 7.48. Kidney area = 0.45 × (A + B) × L. Chlorine = gallons ÷ 10,000 × ppm × product factor.
Questions people ask
How many gallons in a 24 ft round above-ground pool?
At 4 ft of water about 13,500 gallons (π × 12² × 4 × 7.48). At 4.5 ft it is about 15,200 gallons.
How much liquid chlorine raises a pool 1 ppm?
About 12.8 fl oz of 10% sodium hypochlorite per 10,000 gallons. With 12.5% pool chlorine it is about 10.2 fl oz.
How do I find average depth for a sloped pool?
Add the shallow and deep end depths and divide by two. If the deep end is a short hopper rather than a constant slope, this slightly overestimates the volume.
What free chlorine level should a pool have?
The CDC recommends at least 1 ppm in pools and 3 ppm in hot tubs. Many owners target 2 to 4 ppm, more if cyanuric acid (stabilizer) is high.