Convert German degrees of hardness and ppm as calcium carbonate.
Open live calculator →8 °dH equals approximately 142.8 ppm as calcium carbonate.
ppm is expressed as calcium carbonate (CaCO₃).
Translate between two common hardness units used by aquarium tests, species profiles and water reports.
The live tool updates immediately and shows the result in the units commonly used by aquarium keepers around the world.
GH and KH describe different parts of water chemistry.
Confirm which measurement a care guide means.
Use a suitable aquarium test for decisions.
GH (general hardness) measures dissolved calcium and magnesium—what fish physiology cares about. KH (carbonate hardness) measures buffering capacity, which stabilises pH. Both are reported in °dH or ppm, but they are different measurements.
Multiply degrees of German hardness by 17.848 to get ppm as calcium carbonate. So 8 °dH is about 143 ppm.
Soft-water species like many tetras and apistos prefer low GH (under ~8 °dH); livebearers and African rift lake cichlids want hard water (12 °dH and up). Check species guides and match fish to your source water when possible.