Hardness unit converter

mg/L CaCO₃ · gpg · °dH · °fH · mmol/L · °Clark — type in any field.

Hardness is the amount of calcium and magnesium in water, expressed as an equivalent of calcium carbonate (CaCO₃). Countries use different units for the same quantity.

1 °dH (German degree) = 17.85 mg/L · 1 °fH (French degree) = 10 mg/L · 1 gpg (grain per US gallon) = 17.12 mg/L · 1 mmol/L = 100.09 mg/L · 1 °Clark = 14.25 mg/L.

Bands used on this site: soft below 60 mg/L, moderately hard 60–120, hard 120–180, very hard above 180 mg/L.