Tool 509 · Equilibrium & buffer design
pH Calculator
Go beyond “−log concentration.” Solve strong and weak acid/base systems, exact monoprotic buffers, strong-acid/base mixing, or reverse-design a buffer — with water autoionization and transparent assumptions.
Water-awareVery dilute strong acids/bases do not break the calculator.
Exact weak equilibriumNumerical charge/mass-balance solving, not only √KaC shortcuts.
Buffer intelligenceExact ideal solution plus Henderson–Hasselbalch comparison.
Honest scopeActivity effects are flagged instead of hidden.
Strong electrolyte pH with water autoionization
Unlike the usual shortcut, this remains sensible when the acid/base concentration approaches the H⁺/OH⁻ level of pure water.
Water equilibrium / model settings
Default pKw = 14.000 is the standard 25 °C classroom approximation. For other temperatures/conditions, enter an appropriate pKw. Calculations use concentration-based ideal equilibria rather than activity coefficients.