Acids, Bases, pH & Ionic Equilibrium Calculators

All acids, bases, ph & ionic equilibrium calculators in one place.

pH Calculator

Calculate pH, pOH, [H+] and [OH-] for any solution — strong acids, strong bases, weak acids, weak bases, and Henderson-Hasselbalch buffers — with full step-by-step working.

pOH Calculator

Calculate pOH, pH, [OH-] and [H+] for any solution — strong bases, strong acids, weak bases, weak acids, and Henderson-Hasselbalch buffers — with full step-by-step working.

Convert hydrogen ion concentration [H+] to pH in mol/L, mmol/L, µmol/L or nmol/L, convert pH back to [H+] in your chosen unit, and compare two pH values with a built-in acidity ratio tool, with full step-by-step working.

Strong Acid pH Calculator

Find the pH of any strong acid from molarity with common-acid presets, work out the exact dilution needed to reach a target pH, or calculate the combined pH after mixing two acid solutions, with an automatic correction for water autoionization at very dilute concentrations and full step-by-step working.

Strong Base pH Calculator

Find the pH of any strong base from molarity with common-base presets, work out the exact dilution needed to reach a target pH, or calculate the combined pH after mixing two base solutions, with an automatic correction for water autoionization at very dilute concentrations and full step-by-step working.

Weak Acid pH & Ka Calculator

Find the pH and percent dissociation of any weak acid from concentration and Ka, back-calculate Ka and pKa from a measured pH, or find the concentration needed to hit a target pH, with the exact ICE-table quadratic solved every time and full step-by-step working.

Weak Base pH & Kb Calculator

Find the pH, pOH and percent ionization of any weak base from concentration and Kb, back-calculate Kb and pKb from a measured pH, or find the concentration needed to hit a target pH, with the exact ICE-table quadratic solved every time and full step-by-step working.

pKa & pKb Converter

Convert Ka to pKa or pKa back to Ka, convert Kb to pKb or pKb back to Kb, and find the full conjugate acid-base pair — Ka, pKa, Kb and pKb together — from just one known value using pKa + pKb = 14, with acid/base strength classification and full step-by-step working.

Henderson-Hasselbalch Buffer pH

Calculate buffer pH from pKa and the conjugate base/weak acid ratio, work out exactly what ratio (and what concentrations) you need to hit a target pH, or back-calculate pKa and Ka from a measured pH — with a buffer capacity (pKa ± 1) check, common buffer-system presets, and full step-by-step working.

Buffer Capacity Calculator

Calculate buffer capacity (β) from pKa, total concentration and pH, estimate the pH change after adding a known amount of strong acid or base, or find the total concentration needed to hit a target buffer capacity — with a live buffer capacity curve, common buffer-system presets, and full step-by-step working.

Acid-Base Titration Equivalence Point

Find the exact volume of titrant needed to reach the equivalence point and the resulting pH for strong acid/strong base, weak acid/strong base, and weak base/strong acid titrations, with a half-equivalence point check, common weak acid/base presets, a schematic titration curve, and full step-by-step working.

Neutralization Reaction Calculator

Mix any acid with any base and find the limiting reagent, the leftover acid or base, the resulting pH, the salt formed, moles of water produced, and the heat released — with common strong and weak acid/base presets, a calorimetry temperature-rise option, and full step-by-step working.

Polyprotic Acid Equilibrium Solver

Find the exact pH and full species distribution of diprotic and triprotic acids like H2CO3, H3PO4, H2C2O4, and H2SO4 from concentration and Ka1/Ka2/Ka3 using the full charge-balance equation, or explore the alpha-fraction distribution diagram at any chosen pH, with full step-by-step working.

Solubility Product Constant (Ksp)

Calculate the solubility product constant (Ksp) from molar solubility, find molar solubility from Ksp, work out the common-ion effect on solubility, or predict whether mixing two solutions will form a precipitate with a Q vs Ksp check — with 30+ built-in salts and full step-by-step working.

Molar Solubility from Ksp

Find molar solubility directly from Ksp and salt stoichiometry in mol/L, mmol/L, µmol/L, g/L, mg/L, and g/100mL, with an automatic USP-style solubility classification, a 30+ salt comparison ranking chart, and full step-by-step working.

Common Ion Effect Solubility Solver

Find how much a common ion suppresses the molar solubility of any sparingly-soluble salt, enter the common-ion concentration directly or calculate it from a source compound's mass, and see the percent suppression, a full solubility-vs-concentration curve, and complete step-by-step working.

Salt Hydrolysis pH Calculator

Find the pH of any salt solution — salts of a weak acid and strong base, a strong acid and weak base, a weak acid and weak base, or a neutral strong-strong salt — with built-in salt presets, percent hydrolysis, and complete step-by-step working.

Isoelectric Point (pI) Calculator

Find the isoelectric point of any of the 20 standard amino acids from their exact pKa values, or paste a peptide/protein sequence to estimate its overall pI from residue counts, with a net-charge-vs-pH curve and complete step-by-step working.