Instantly convert hydrogen ion concentration $[H^+]$ into pH. This calculator also provides the corresponding pOH and hydroxide ion $[OH^-]$ concentrations for a complete profile of your acid-base solution.
The pH Scale
The pH scale is a logarithmic measure of the acidity or basicity of an aqueous solution. Because hydrogen ion concentrations can range from $1$ M down to $1 \times 10^{-14}$ M, a logarithmic scale provides a manageable number between 0 and 14.
Where:
=
Hydrogen Ion Concentration (mol/L)Temperature Dependence
The standard pH scale from 0 to 14 is specifically calibrated for water at $25^\circ\text{C}$ (298 K), where the autoionization constant of water ($K_w$) is exactly $1.0 \times 10^{-14}$.