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Home & Basement

Water Softener Size Calculator

Enter household size, water hardness, and regeneration target to estimate softener capacity.

Last updated: May 2026

Unit system Switch between U.S. customary and metric units. Your choice is remembered on other calculators.

Household and water details

Hardness is usually listed in grains per gallon (GPG) on a water test.

people
GPG
Advanced settings
gal/day
days

Buying and sizing notes

How to use this estimate

What this includes

  • The required inputs shown on this page
  • common planning assumptions
  • optional advanced adjustments where provided

What it does not include

  • site-specific professional design
  • local code approval
  • manufacturer-specific requirements
  • installation quality

Common mistakes

  • Leaving a required input at the default when your situation is different
  • ignoring product labels or ratings
  • treating the estimate as an exact final answer

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