Water Softener Sizing Calculator
Size a water softener by grain capacity so it regenerates efficiently — not too often (wasteful) and not too rarely (hard water breakthrough).
Water Softener Sizing Calculator
Estimate the grain capacity you need so the softener regenerates about weekly — efficient and effective.
Your recommended softener size will appear here.
Recommended capacity
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grain unit
Daily softening need
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grains / day
Based on ~75 gallons per person per day and roughly weekly regeneration; iron or high usage may require a larger unit. This tool provides a rough estimate for general informational purposes only and is not professional advice, a guarantee, or a quote. Results may not reflect your specific situation. Always confirm with a licensed HVAC professional before making any purchase or decision. See our Terms of Service for details.
Frequently Asked Questions
What size water softener do I need?
Multiply the number of people by daily water use (about 75 gallons each) and your water hardness in grains per gallon. Most families land on a 32,000–48,000 grain unit.
How do I find my water hardness?
Check your utility’s water quality report or use an inexpensive test kit. Hardness is measured in grains per gallon (gpg); above 7 gpg is considered hard.