Water softener and well water calculators
Size a water softener, price it, work out your salt and convert hardness units, all with the math shown. Every number comes from manufacturer spec sheets, extension services and industry standards, and each page lists its sources.
Photo: Swanky Fella / Unsplash
Most popular
Grains you need from your household and hardness, at your real salt setting.
Unit, install, salt and service, with a 10-year total and a quote check.
Pounds per month, bags per year and yearly cost for your softener.
gpg, ppm, mg/L, mmol/L and German or French degrees in one step.
Water softeners
View allHard water above 7 gpg leaves scale in heaters and fixtures. Start with your hardness, then size, price and run your softener.
Grains you need from your household and hardness, at your real salt setting.
Unit, install, salt and service, with a 10-year total and a quote check.
Pounds per month, bags per year and yearly cost for your softener.
gpg, ppm, mg/L, mmol/L and German or French degrees in one step.
Well water
View allPrivate well? Size the pressure tank so your pump runs long enough each cycle.
Popular answers
48,000 grains
A family of 4 with 15 gpg water needs a 48,000-grain softener at a 9 lb salt setting.
Size yoursAbout 590 lb
Salt a family of 4 with 15 gpg water uses in a year on a metered softener.
Work out yoursWhy trust these calculators
Sources on every page
Each calculator lists the spec sheets, standards and extension guides its numbers come from, with the date we checked them.
The math is shown
Open "Show the math" under any result to see the formula with your own numbers.
Tested before publishing
Every formula has automated tests built from the worked examples, tables and FAQ numbers on its page.
Latest updates
- Well Pressure Tank Size CalculatorOct 20, 2026
- Water Hardness ConverterOct 20, 2026
- Water Softener Salt CalculatorOct 20, 2026
- Water Softener Cost CalculatorOct 20, 2026
- Water Softener Size CalculatorOct 20, 2026
- Well water calculatorsOct 20, 2026
Photo credits
- A glass being filled with tap water at a kitchen sink by Swanky Fella / Unsplash
- Row of resin treatment tanks with control valves and blue piping by Alexey Demidov / Pexels
- Gloved hands fitting a threaded pipe connection during an installation by Sergei Starostin / Pexels
- Close-up of coarse white salt crystals by Charles Deluvio / Unsplash
- Water sample in a glass beaker with a pipette by Hans Reniers / Unsplash
- Water pressure gauge in psi on a plumbing manifold by Anton Savinov / Unsplash