Science & Environment
Water Hardness GPG / mg/L CaCO3 & Softener Salt Calculator
Convert water hardness between grains per gallon and mg/L CaCO3, and estimate softener salt use.
Your inputs
Change any value to update the result instantly.
Hardness in GPG
14.62 gpg
Hardness mg/L CaCO3
250 mg/L
Estimated softener salt use
421.05 kg/month
Daily water usage
300 gal/day
Formula and working
GPG = mg/L CaCO3 ÷ 17.1; Salt (kg/month) = GPG × gallons/day × 30 ÷ capacity factor
- 1
Collect the inputs
Hardness = 250 mg/L CaCO3; Daily water usage = 300 gal/day; Salt use factor = 0.0032 kg/(gpg·gal)
- 2
Apply the formula
GPG = mg/L CaCO3 ÷ 17.1; Salt (kg/month) = GPG × gallons/day × 30 ÷ capacity factor
- 3
Result
Hardness in GPG = 14.62 gpg
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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