pH

Calculate pH from hydrogen ion concentration using the base-10 logarithm.

How this calculator works

Enter the values for value, rate (%) and review the units before calculating.

Formula / method

pH = −log10[H⁺]

Worked example

A hydrogen ion concentration of 0.001 mol/L gives pH 3.

Assumptions and limitations

The supplied concentration is positive and represents hydrogen-ion activity closely enough for this estimate.

Very concentrated solutions require activity corrections; pH is not a direct measure of safety.