conversion
Hardness and alkalinity converter
Convert between German degrees, ppm as calcium carbonate and milliequivalents per litre — for both GH and KH.
8 °dH = 142.8 ppm CaCO₃ = 2.853 meq/L
As general hardness, that is Moderately hard water. The same arithmetic applies to KH, but GH and KH measure different things — converting units does not convert one into the other.
Working — every step, so you can check it
- German degrees
- 8 °dH
- ppm as CaCO₃
- 8 × 17.848 = 142.8 mg/L
- meq/L
- 142.8 ÷ 50.043 = 2.853 meq/L
Formula
- 1 °dH = 17.848 mg/L as CaCO₃ (10 mg/L CaO, converted by the molar mass ratio CaCO₃/CaO)
- 1 meq/L = 50.043 mg/L as CaCO₃ (half the formula mass of CaCO₃)
- °dH → meq/L: value × 17.848 ÷ 50.043
Assumptions
An estimate whose assumptions are invisible is indistinguishable from a guess.
- Hardness is expressed as calcium carbonate equivalent, which is the standard convention.
- The same numeric conversion applies to GH and KH because both are reported in German degrees against the same CaCO₃ reference.
Limitations
Where this calculation stops being reliable. Read these before acting on a result.
- GH and KH measure different things. Converting units does not convert one into the other.
- American, French, Clark and other national degrees use different definitions and are not handled here.