Runs on this device. Inputs are not uploaded or saved. Results rounded for display.
How to use it
- Measure the inputs in the units shown. Keep a note of your original recipe.
- Change the relevant input and calculate. Compare the answer with the worked example below.
- Use the output within the stated limits; reset to restore the example inputs.
Worked example
20 mg/L calcium and 5 mg/L magnesium gives 49.94 + 20.59 = 70.53 ppm as CaCO3.
Assumptions and limits
Uses rounded molar-mass factors and assumes calcium/magnesium dominate hardness. Does not calculate alkalinity or TDS and cannot specify a complete mineral recipe.
Questions
What does this result establish?
Convert ion concentrations to CaCO3 equivalents: calcium × 2.497 and magnesium × 4.118; add for estimated total hardness. It provides the stated arithmetic or random ordering; it is not a taste or equipment certification.
What measurements should I use?
Calcium ions (mg/L); Magnesium ions (mg/L). Keep the units consistent rather than copying a number from a differently labelled recipe.
Why is an input rejected?
Blank, non-finite, negative or out-of-domain measurements cannot produce a valid answer. Each field has a bounded range. Incompatible combinations show an explanation instead of retaining a previous result.
Can I use this without an account?
Yes. Once this page and its modules load, the calculation runs locally without accounts, external APIs or input storage. Reloading restores the defaults.
Related tools
Two-Source Water Blend
Each blended concentration is A × A fraction + B × B fraction. Volume splits follow that fraction.
Open tool →Water Hardness Unit Converter
Convert CaCO3-equivalent concentration using 17.848 ppm per German degree, 17.118 ppm per US grain/gallon, and 10 ppm per French degree.
Open tool →Brewing Temperature and Volume Units
Fahrenheit = Celsius × 9/5 + 32. Convert volume using the explicitly distinguished US and Imperial fluid ounces.
Open tool →