Chemistry & units
Water hardness converter
Convert between the five hardness units in common international use, with the resulting classification.
Result
mg/l as CaCO₃ (ppm)
250.0
German degrees
14.01°dH
French degrees
25.00°fH
Clark degrees
17.54°Clark
Grains per US gallon
14.60gpg
Classification
Hard
Significant scaling on heating elements and in kettles.
Method
Converts through a common base of milligrams per litre as calcium carbonate. 1 °dH = 17.848 mg/l; 1 °fH = 10 mg/l; 1 °Clark = 14.254 mg/l; 1 grain per US gallon = 17.118 mg/l.