Calcium and Magnesium to Water Hardness
Convert with explicit units, definitions and assumptions.
Formula
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Calcium and magnesium contribution only; not an assessment of drinking-water safety.
Example Calculation
- Calcium: 40 mg/L
- Magnesium: 12 mg/L
40 mg/L calcium and 12 mg/L magnesium gives 149.296 mg/L as CaCO₃.
Method references
Frequently asked questions
How do I use this calculator?
Enter calcium, magnesium. The result updates automatically. Use Reset to restore the example values.
What method does it use?
hardness as CaCO₃ = 2.497 × calcium + 4.118 × magnesium. Calcium and magnesium contribution only; not an assessment of drinking-water safety.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.