Chemistry calculators
Chemistry tools cover the calculations behind lab work and coursework: molar mass and stoichiometry, limiting reagents and percent yield, empirical formulas, molarity and dilution, pH and buffers, equilibrium, colligative properties, the Beer-Lambert law, reaction kinetics and cell potentials, plus a periodic table and a significant figures tool.
17 tools · Updated October 21, 2026
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The mole and stoichiometry
The mole connects the mass you can weigh to the number of particles that react. One mole contains 6.02214076 × 10²³ particles, and its mass in grams equals the compound's molar mass. The Molar Mass Calculator adds up atomic masses from a formula, and the Periodic Table gives the values for each element.
Stoichiometry follows a fixed path: grams to moles, moles of one substance to moles of another using the coefficients of the balanced equation, then moles back to grams. The Stoichiometry Calculator follows that path, the Limiting Reagent Calculator finds which reactant caps the product, and the Percent Yield Calculator compares what you collected with the theoretical maximum.
Solutions, dilution and measuring concentration
Molarity is moles of solute per liter of solution, not per liter of solvent. To make a solution, use the Molarity Calculator to find the mass needed; to dilute a stock solution, use C₁V₁ = C₂V₂ in the Dilution Calculator, which tells you how much stock to measure and how much solvent to add.
In the lab, concentration is often measured rather than calculated. The Beer-Lambert law relates absorbance to concentration and path length, which is how spectrophotometers work. Dissolved particles also lower the freezing point and raise the boiling point of a solvent, effects the Colligative Properties Calculator quantifies.
pH, buffers and equilibrium
pH is the negative base-10 logarithm of the hydrogen ion concentration, so each unit is a tenfold change. At 25 °C, pH + pOH = 14. The pH Calculator handles strong acids and bases directly; weak acids require an equilibrium calculation because they only partly dissociate.
A buffer resists pH change because it contains both a weak acid and its conjugate base. The Henderson-Hasselbalch equation, pH = pKa + log([A⁻]/[HA]), gives its pH, and buffers work best within about one pH unit of the pKa. For general equilibria, the Chemical Equilibrium Calculator builds an ICE table and solves for equilibrium concentrations.