Cactus2000 | About | Email

Converter for hardness of water

°dH (German degree of hardness, 10 mg CaO/l)
°fH (French degree of hardness, 10 mg CaCO3/l)
°e (English degree of hardness, grain CaCO3/gal(UK))
ppm (mg CaCO3/l)
mmol/l (millimol per litre)
mval/l (millival per litre)
gr/gal(US) (grain CaCO3/gal(US))
mg CaO/l
mg CaCO3/l
mg Ca2+/l
mg Mg2+/l

The results have been rounded to significant digits.

Hardness of water is a measure for the content of calcium and magnesium in water. The small contribution of magnesium usually is expressed as calcium as in the degrees of hardness (at the top) and the concentrations of Ca2+, CaO and CaCO3 (at the bottom). Unfortunately, the classification of the degrees of hardness to water quality (soft, slightly hard, hard, very hard) is different in many countries.

Usage: Type the value to convert into the field, behind which you find the unit. Click on any empty space in the window or on the "calculate" button. Read the result in the other fields. Use the "reset" button to reset your calculation.

Example: A mineral water contains 140 mg Ca2+/l and 30 mg Mg2+/l. What is its degree of hardness? You have to calculate twice. At first, type "140" into the field behind which "mg Ca2+/l" is written. Click on any empty space in the window or on the "calculate" button. Read the result for calcium in the other fields (e.g. English degree of hardness: 24.5 °e or 3.49 mmol/l). For the calculation of the magnesium type "30" into the field in front of "mg Mg2+/l". After another click you see the result for magnesium (e.g. English degree of hardness: 8.7 °e or 1.23 mmol/l). You have to add both results to receive the total hardness, e.g. English degree of hardness: 33.2 °e or 4.72 mmol/l.

- Large and small numbers are written exponentially. As example 2.3e5 = 2.3⋅105 = 230000 or 4.5e-5 = 4.5⋅10-5 = 0.000045.
- There is no warranty for the conversion. Cactus2000 is not responsible for damage of any kind caused by wrong results.
- Please send an email if you have suggestions or if you would like to see more conversions to be included.

- A collection of all Cactus2000-converters running offline may be ordered for a price of € 15.-. A test version is available for download for free.

© Bernd Krüger, 14.07.2004, 18.08.2016

Valid HTML 4.01 Transitional

Unit converters

Search for Cactus2000 unit converters:

New in July 2014
- Heat index
- Speed (calculations)

Physics (A-F)
Physics (G-P)
Physics (R-W)
Date and time


Follow Cactus2000 on
Google+, Twitter

Lerning languages
Offline products
Conjugation tables
- Time of sunset
- Vehicle licence plates

About Cactus2000

Cactus2000 Euro converter:
Now with
19 old currencies

NEW: Litas
To the top

Bernd Krüger, 2016