Pool & hot tub calculators
Free, no sign-up. Exact amounts for your water.
Salt pool calculator
How much pool salt to add for your salt chlorine generator.
Pool chemical calculator
Type your test results and see everything to add, in a safe order.
Pool shock calculator
How much chlorine it takes to shock your pool, from your stabilizer level.
Pool chlorine calculator
How much liquid chlorine, bleach or granules to raise free chlorine.
Hot tub chemical calculator
Test results in, exact spa doses out — chlorine or bromine.
Pool volume calculator
How many gallons your pool holds, from its length, width and depth.
pH calculator
How much acid to lower pH, or pH Up to raise it.
Alkalinity calculator
How much baking soda raises alkalinity — or acid to lower it.
Calcium hardness calculator
How much calcium chloride raises calcium hardness.
Stabilizer calculator
How much stabilizer (cyanuric acid) to add, and when to stop.
Every amount comes from the chemistry of what is in the bottle. The product label always wins.