Water softener calculators

A water softener swaps the calcium and magnesium in hard water for sodium or potassium as water passes through a tank of resin beads. When the beads are full, the softener rinses them with brine from the salt tank. That cycle is called regeneration, and it's what every number on these pages is built around.

Start with your hardness. Your water utility's yearly water quality report lists it, usually in mg/L. On a well, use a test strip or a lab test. Then size the softener from your household and hardness, check what it should cost to buy and install, and work out the salt it will use each year.

Three numbers decide most of it: hardness in grains per gallon, the number of people in the home, and the salt setting on the control valve. A lower salt setting softens more water per pound of salt but needs a slightly larger tank. The calculators below let you see that trade-off for your own home.