Calculadora de Dureza da Água
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
H = (Ca/40,08 + Mg/24,31) × 100,09
About this calculator
The Water Hardness Calculator determines total water hardness in ppm of CaCO₃, based on the concentrations of calcium (Ca) and magnesium (Mg) provided. Water hardness is an important parameter for assessing water quality, influencing everything from taste to scale formation in pipes and appliances.
The calculation uses the formula: H = (Ca/40.08 + Mg/24.31) × 100.09, where Ca and Mg are concentrations in ppm. The factor 100.09 is the molar mass of CaCO₃. This method converts the masses of Ca and Mg into CaCO₃ equivalents, standardizing total hardness measurement.
This tool is useful for water treatment professionals, homeowners with well water, and industries that need to monitor water hardness to prevent equipment damage. It also helps in correctly dosing water softeners and evaluating water for aquariums or pools.
Precautions: Ensure Ca and Mg concentrations are in the same unit (ppm). The formula assumes all hardness is due to Ca and Mg; other ions like strontium and barium may contribute but are rare. For water with high iron content, consider additional analyses.
Frequently asked questions
What does water hardness in ppm of CaCO₃ mean?
It is a measurement that expresses the total concentration of calcium and magnesium ions equivalent to the mass of calcium carbonate. The higher the value, the 'harder' the water.
What is the difference between temporary and permanent hardness?
Temporary hardness is caused by bicarbonates and can be removed by boiling. Permanent hardness is due to sulfates and chlorides and is not removed by boiling. This calculator measures total hardness without distinguishing types.
How do I obtain Ca and Mg concentrations?
They can be obtained through water test kits, laboratory analyses, or utility reports. Ensure the values are in ppm (mg/L).
Does water hardness affect health?
Hardness is not harmful to health; in fact, calcium and magnesium are beneficial. However, very hard water can cause scaling and reduce the efficiency of soaps and detergents.
What should I do if my water is too hard?
You can use a water softener (ion exchange) or specific filters. Consult a professional to evaluate the best solution for your case.