Calculator
Softener size calculator
People × daily gallons × hardness (gpg) × days between regenerations → rough grain capacity. Always recheck with a kit and your valve manual.
Result
Enter values and calculate
Output appears here: daily grains, capacity needed, and next common tank size.
Disclaimer
- Starting estimate only—not a guarantee or engineering stamp.
- Peak flow, iron bacteria, and valve type change real needs.
- Install and main cuts may require a licensed plumber.
- Common sizes used: 16k, 24k, 32k, 40k, 48k, 64k, 80k, 96k grains.
Formula: people × gpd × gpg × days between regenerations (optional iron adjustment). Sources and limits documented for editors in the repo tools formulas file.
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