About this tool
Enter any one of pH, pOH, [H+] or [OH-] and the rest are computed live in your browser using pH = -log10[H+], pH + pOH = 14 and [H+][OH-] = 1e-14.
Frequently asked questions
Which value should I enter?
Just one — type a pH, pOH, hydrogen-ion or hydroxide-ion concentration and the other three fields and the result update automatically.
How is acidic versus basic decided?
A pH below 7 is acidic, exactly 7 is neutral and above 7 is basic, based on the standard scale at 25 °C where the ion product of water is 1×10⁻¹⁴.