Determine the hydrogen ion concentration, [H+], in moles per liter
Use the formula pH = -log10[H+]
If given pOH, compute pH = 14 – pOH
For strong acids, assume complete dissociation to find [H+]
For weak acids, use the acid dissociation constant, Ka, and an equilibrium calculation to find [H+]
For strong bases, find [OH-] first, then compute pOH and convert to pH
For weak bases, use the base dissociation constant, Kb, and an equilibrium calculation to find [OH-]
For buffered solutions, use the Henderson-Hasselbalch equation: pH = pKa + log10([A-]/[HA])
For mixtures, account for dilution and combine all sources of H+ or OH- before calculating pH
For temperature other than 25°C, use the appropriate pH + pOH relationship for that temperature