Enter your water's Calcium (Ca²⁺) and Magnesium (Mg²⁺) Concentrations with your preferred units into the Water Hardness Calculator to get Total Hardness, Grains per Gallon, Classification, and the individual Ca/Mg Hardness Contributions.
Total Water Hardness
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Hardness (Grains per Gallon)
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Water Classification
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Calcium Hardness Contribution
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Magnesium Hardness Contribution
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Water hardness refers to the concentration of dissolved calcium and magnesium ions in water. Hard water can cause scale buildup in pipes and appliances, reduce soap effectiveness, and affect the taste of water.
You can use water test strips, digital TDS meters, or have your water professionally tested. Many municipal water suppliers also provide water quality reports that include hardness levels.
PPM (mg/L as CaCO₃) is the most common unit, gpg (grains per gallon) is popular in the US, while °dH (German degrees) and °fH (French degrees) are used in Europe. All measure the same thing in different scales.
Soft water: 0-60 ppm, Moderately hard: 61-120 ppm, Hard: 121-180 ppm, Very hard: >180 ppm. These classifications help determine if water treatment is needed.
White scale deposits on faucets and showerheads, soap scum buildup, reduced lather from soap, dry skin and hair, and spotted dishes after washing are typical signs of hard water.
Hard water causes mineral buildup in pipes, reducing water flow over time. It can also shorten the lifespan of water heaters, dishwashers, and washing machines by causing scale accumulation.
Water softeners that use ion exchange are the most effective for removing calcium and magnesium. Salt-free conditioners can help with scale control, while reverse osmosis systems provide comprehensive water purification.
This calculator provides accurate results when you input correct calcium and magnesium concentrations. For the most precise measurements, professional water testing is recommended, especially for critical applications.