Pool & hot tub calculators
Pool volume, chlorine, salt, water replacement and hot tub chemical amounts. 5 free tools, each with its formula and sources.
- Pool Volume CalculatorGallons or litres in rectangular, round, oval and kidney pools, including sloped floors.
- Pool Chlorine CalculatorHow much liquid chlorine, bleach or granules raises free chlorine, and the level to aim for.
- Hot Tub Chlorine & Bromine CalculatorSmall-volume doses in grams, ounces and millilitres for spas and hot tubs.
- Pool Salt CalculatorBags of salt to bring a saltwater pool up to its target level.
- Pool Drain & Refill CalculatorHow much water to replace to lower stabilizer (CYA), calcium hardness, salt or TDS.