Chemistry Calculators

Calculate the molecular weight of any chemical formula using IUPAC 2021 atomic weights. Supports all 118 elements, parentheses, brackets, and hydrate notation — Free online molecular weight calculator.

Calculate the molar mass of any chemical formula using standard IUPAC 2021 atomic weights. Supports chemical subscripts, nested parentheses, square brackets, and hydrates. Free online molar mass calculator — no signup required.

Solve the dilution equation C1V1 = C2V2 for stock or diluted concentration or volume. Features a solute molecular weight converter, multi-unit selectors, and interactive beaker visuals. Free online dilution calculator.

Calculate molar concentration, mass, volume, or moles of solute instantly. Features a built-in chemical formula weight converter and multi-unit support. Free online molarity calculator.

Calculate the pH, pKa, or concentrations of a buffer solution using the Henderson-Hasselbalch equation. Supports acidic and basic buffer systems. Free online buffer pH calculator.

Solve stoichiometry problems from balanced chemical equations. Enter reactants and products to automatically balance the equation, then input a given amount (in grams, moles, or molecules) of any substance to compute the corresponding amounts for all other species. Free online stoichiometry calculator — no signup required.

Calculate the percent composition by mass of each element in a chemical compound. Enter any chemical formula to get element percentages, molecular weight, and step-by-step mathematical breakdown with an interactive donut chart. Free online percent composition calculator.

Calculate the empirical formula and molecular formula of a chemical compound from mass percentages or weights. Search standard atomic weights, solve ratios, and see step-by-step calculations. Free online empirical formula calculator.

Calculate the limiting reagent, theoretical yield, and percent yield of a chemical reaction. Input reactant amounts (in grams or moles), stoichiometric coefficients, and product parameters to find limiting/excess species and step-by-step conversions. Free online limiting reagent calculator.

Calculate boiling point elevation and freezing point depression of solutions using colligative property equations. Enter molality, van't Hoff factor, and solvent constants to solve for temperature changes and final values. Free online boiling & freezing point calculator.

Solve for any variable in the Ideal Gas Law (PV = nRT), Boyle's Law, Charles's Law, Gay-Lussac's Law, Avogadro's Law, and Combined Gas Law. Choose custom units for pressure, volume, temperature, and quantity, and view step-by-step algebraic derivations with an interactive molecular simulation. Free online gas laws calculator.

Solve standard reaction enthalpy changes (ΔH°rxn) using Hess's Law. Specify reactants and products, select compound enthalpies of formation (ΔH°f) from our database, or write custom values. View potential energy profile diagrams. Free online enthalpy change calculator.

Generate ground-state electron configurations for all 118 chemical elements. Search by element symbol, name, or atomic number to view full configurations, abbreviated noble gas notations, shell occupancy layouts, and interactive orbital spin diagrams. Free online electron configuration calculator.

Determine the oxidation state/number of each element in a chemical formula or polyatomic ion. Features support for neutral compounds, charged ions, complex molecules, and a step-by-step rule-based solver. Free online oxidation state calculator.

Calculate nuclear decay pathways, daughter isotopes, half-life, decay constants, and remaining radioactive activity after a specific time duration. Supports alpha, beta, positron, and gamma decay types with step-by-step decay law breakdown. Free online nuclear decay calculator.