How to use the ionic strength calculator
Compute ionic strength of a salt solution. Enter cation concentration, cation charge, anion concentration, anion charge in the fields above; the ionic strength is computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- c1 — Cation concentration (mol/L)
- z1 — Cation charge
- c2 — Anion concentration (mol/L)
- z2 — Anion charge
Worked example
With cation concentration = 0.1 mol/L, cation charge = 1, anion concentration = 0.1 mol/L, anion charge = -1, the calculator gives ionic strength ≈ 0.1 mol/L.
Frequently asked questions
What is the formula for the ionic strength calculation?
Ionic strength (mol/L) = 0.5 × (c1 × z1 × z1+c2 × z2 × z2). Here c1 is cation concentration (mol/L), z1 is cation charge, c2 is anion concentration (mol/L), z2 is anion charge.
What inputs do I need for the ionic strength calculator?
You need cation concentration in mol/L, cation charge, anion concentration in mol/L, anion charge. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.