How do I convert my KH/GH reading from ppm to degrees (or degrees to ppm)? KH or GH readings in parts per million (ppm) can be converted to degrees by dividing them by 17.86. For example, if your KH tests as 120 ppm, this means your KH is 6.7 degrees.
Conversion from degrees to ppm can be accomplished by multiplying by 17.86.