How to use the ph calculator
Compute pH, pOH and ion concentrations from hydrogen ion concentration. Enter hydrogen ion concentration [h⁺] in the field above; the ph, poh, [oh⁻] are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- H — Hydrogen ion concentration [H⁺] (mol/L)
Worked example
With hydrogen ion concentration [h⁺] = 0.001 mol/L, the calculator gives ph ≈ 3; poh ≈ 11; [oh⁻] ≈ 1 × 10⁻¹¹ mol/L.
Frequently asked questions
What is the formula for the ph calculation?
pH = -log10(H). pOH = 14-[pH]. [OH⁻] (mol/L) = 10^(-[pOH]). Here H is hydrogen ion concentration [h⁺] (mol/L).
What inputs do I need for the ph calculator?
You need hydrogen ion concentration [h⁺] in mol/L. 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.