calcs.homes

Pool & spa calculators

18 free tools for pool sizing, chemistry dosing, and equipment sizing.

Pool sizing

Pool Gallons Calculator
Quick gallons for a rectangle, round, oval, or kidney pool.
Open calculator →
Pool Volume CalculatorMost popular
Full volume with a sloped deep end, or an above-ground preset.
Open calculator →

Pool chemistry

Pool Chemical CalculatorAll-in-one
Dosing for chlorine, alkalinity, calcium, stabilizer, or salt in one tool.
Open calculator →
Pool pH Calculator
Soda ash or muriatic acid dose to hit your target pH.
Open calculator →
Pool Salt Calculator
Pounds of salt to hit your saltwater chlorinator's target.
Open calculator →
Pool Alkalinity Calculator
Raise or lower total alkalinity with baking soda or acid.
Open calculator →
Muriatic Acid Pool Calculator
Acid dose for either pH or total alkalinity adjustment.
Open calculator →
Pool Shock Calculator
Shock dose for routine maintenance, algae, or heavy recovery.
Open calculator →
Pool Chlorine Calculator
Raise free chlorine ppm with liquid or granular product.
Open calculator →
Baking Soda Calculator
Raise total alkalinity with plain baking soda.
Open calculator →
Pool LSI Calculator
Langelier Saturation Index — is your water balanced?
Open calculator →
Cyanuric Acid Calculator
Raise stabilizer / conditioner (CYA) level.
Open calculator →
Calcium Chloride Calculator
Raise calcium hardness to protect plaster and equipment.
Open calculator →

Pool equipment

Pool Pump Size Calculator
Flow rate needed and a recommended pump horsepower.
Open calculator →
Pool Heater Size Calculator
BTU sizing from surface area and desired temperature rise.
Open calculator →
Pool Pump Run Time Calculator
How many hours a day to run your pump.
Open calculator →
Pool Evaporation Calculator
Daily and weekly water loss from evaporation.
Open calculator →
Pool Pump Electricity Cost Calculator
What running your pump actually costs, monthly and yearly.
Open calculator →