MCPCalc

pH & Buffer Calculator

Compute pH, pOH, and percent ionization for strong acids/bases, weak acids/bases, and Henderson-Hasselbalch buffers.

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What This Calculator Does

This calculator covers the most common introductory acid-base cases: strong acids, strong bases, weak acids, weak bases, and buffer mixtures handled with the Henderson-Hasselbalch equation.

It combines Calculation Mode, Acid Concentration, Base Concentration, Ka to estimate pH, pOH, [H+].

Formula & Method

Core equations: pH=−log⁡10[H+]\mathrm{pH}=-\log_{10}[H^+], pOH=−log⁡10[OH−]\mathrm{pOH}=-\log_{10}[OH^-], and for a buffer pH=pKa+log⁡10([A−][HA])\mathrm{pH}=pK_a+\log_{10}\left(\frac{[A^-]}{[HA]}\right).

Notation used in the formulas: RR = pH; x1x_{1} = Calculation Mode; x2x_{2} = Acid Concentration; x3x_{3} = Base Concentration; x4x_{4} = Ka; x5x_{5} = Kb; x6x_{6} = [HA] for Buffer.

Method summary: inputs are normalized to consistent units, core equations are evaluated, then secondary values are derived and rounded for display.

Use it when comparing simple acid-base scenarios or estimating the pH shift produced by changing acid and conjugate-base concentrations.

Reference Book

Chemistry: The Central Science

Theodore E. Brown, H. Eugene LeMay, Bruce E. Bursten, Catherine Murphy, Patrick Woodward, and Matthew E. Stoltzfus · Pearson

A widely used general chemistry text covering stoichiometry, gases, solutions, acids and bases, and electrochemistry.

View Book

Inputs Used

  • Calculation Mode: Used directly in the calculation.
  • Acid Concentration: Used directly in the calculation.
  • Base Concentration: Used directly in the calculation.
  • Ka: Used directly in the calculation.
  • Kb: Used directly in the calculation.
  • [HA] for Buffer: Used directly in the calculation.
  • [A-] or [BH+] for Buffer: Used directly in the calculation.

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pH & Buffer Calculator: Formula & Use Cases | MCPCalc