Water Softener Grain Capacity Calculator
Enter your household size and water test results to find the correct softener size.
18+
150
010
Recommended Softener Size
40,000 Grain
Step 0: Confirm Your Numbers
DIY screening: well water test strips (16-in-1 or 17-in-1) give a quick baseline for hardness, iron and pH before you size a softener.
Certified testing: for nitrates, bacteria or heavy metals, book a certified lab test.
This is an engineering estimate based on standard sizing formulas, not a substitute for a certified water test. We may earn a commission from Amazon links at no extra cost to you. Full Disclosure.
Related Sizing and Buying Guides
- What to check before buying a well water softenerValves, resin, certifications and iron ratings.
- Sediment pre-filters that protect a softenerSand and grit foul resin and valves without one.
- Does a water softener remove iron?How much iron a softener can handle, and when it cannot.
- Salt-free conditioners vs. salt-based softenersWhat each one really does to hard water.
- Measure your peak flow rate (GPM)The softener valve has to keep up with it.