Calculator directory
Chemistry Calculators
ChemCalculator is a free online chemistry calculator library for students, teachers, laboratory professionals, and scientists. Use our molar mass calculator, chemical equation balancer, and tools for stoichiometry, solution concentration, acids and bases, gas laws, and analytical chemistry. Each calculator shows the formula and method behind the answer and uses reviewed scientific data, so every result is reproducible and easy to verify.
Relative Formula Mass
Relative formula mass (Mr) is the sum of the relative atomic masses of all atoms in a formula. Calculate it, then convert between mass, moles, and particles.
- Molecular Weight CalculatorEnter a chemical formula. The calculator gives its molar mass, molecular weight, atom count, and element composition.
- Molar Mass CalculatorCalculate molar mass from an explicit chemical formula using versioned atomic-weight data.
- Grams to Moles CalculatorConvert a sample mass to moles from its chemical formula or molar mass.
- Moles to Grams CalculatorConvert moles to a selected mass unit from a chemical formula or molar mass.
- Moles CalculatorCalculate moles from an amount, sample mass, or particle count.
- Percent Composition and Empirical FormulaFind the empirical formula from percent composition or element masses. See the percent composition formula and worked problems.
- Find Molecular Formula from Empirical FormulaFind the molecular formula from the empirical formula and molar mass. Divide the molar mass by the empirical formula mass, then multiply the subscripts.
Reactions & Stoichiometry
Balance reactions and follow conserved amounts through stoichiometric ratios and yield.
- Chemical Equation BalancerBalance molecular or ionic equations with verified whole-number coefficients.
- Stoichiometry ProblemsPractice stoichiometry problems with step-by-step answers. Check mole, gram, limiting reactant, and percent yield problems with the calculator.
- Chemical Reaction CalculatorBalance chemical equations, classify reaction patterns, scale quantities, and find limiting reactants with exact stoichiometry.
- Limiting Reagent CalculatorFind the limiting reactant, excess material, and maximum product for a reaction.
- Theoretical Yield CalculatorCalculate theoretical product mass from a balanced reaction and one reactant quantity.
- Percent Yield CalculatorCalculate percent yield, actual yield, or theoretical yield from the other two values.
Solutions & Concentration
Prepare and characterize solutions using concentration and dilution relationships.
- Molarity CalculatorCalculate molarity, solute amount, or solution volume from the known values.
- Molar Dilution CalculatorCalculate a molar dilution with M1V1 = M2V2. Find the stock volume, final molarity, or diluent to add in M, mM, or µM.
- Concentration CalculatorCalculate molarity, mass concentration, percent concentration, ppm, or ppb.
- Serial Dilution CalculatorCreate a stage-by-stage serial dilution plan with transfer and diluent volumes.
- Molarity and MolalityCalculate molarity and molality for the same solution. Compare mol/L and mol/kg, and convert between them with the solution density.
- Normality CalculatorCalculate reaction-specific normality from molarity, equivalents, or equivalent weight.
- PPM CalculatorCalculate ppm by mass, volume, moles, density, percent, or ppb.
Acids, Bases & Equilibrium
Calculate ion concentrations, pH, buffers, and chemical equilibria.
- pH CalculatorCalculate pH, pOH, and ion concentrations for strong or weak acids and bases.
- pOH CalculatorCalculate pOH, pH, and ion concentrations for strong or weak acids and bases.
- Henderson-Hasselbalch CalculatorCalculate pH, pKa, acid amount, or conjugate-base amount for a buffer.
- How Does a Buffer Solution Resist Change in pHA buffer resists pH change because its conjugate base neutralizes added acid and its weak acid neutralizes added base. Test it below.
- Equilibrium Constant CalculatorBuild the equilibrium expression and calculate K from species activities.
- Reaction Quotient CalculatorCalculate Q, compare it with K, and predict the reaction direction.
Gas Laws & Physical Chemistry
Relate pressure, volume, amount, temperature, density, and time-dependent change.
- Ideal Gas Law CalculatorCalculate pressure, volume, amount, or temperature with PV = nRT.
- Gas Law CalculatorUse Boyle, Charles, Combined, Avogadro, or Gay-Lussac gas laws.
- Boyle's Law CalculatorCalculate any pressure or volume in P1V1 = P2V2.
- Example Charles LawSee Charles law examples from real life and worked example problems. Solve V1/T1 = V2/T2 for any volume or temperature.
- Density CalculatorCalculate density, mass, or volume with unit conversion.
- How to Calculate Half Life for Zero OrderFor a zero-order reaction, half-life is t1/2 = [A]0 / 2k. Enter the initial concentration and rate constant to calculate it.
- Sig Fig SolverSolve sig fig problems. Count significant figures, round to a set number, or add, subtract, multiply, and divide with sig fig rules.
Electrochemistry
Connect reaction quotients, electron transfer, and electrical potential.
Atomic Chemistry
Explore elements, electron configurations, and oxidation states.
Analytical Chemistry
Inspect isotope patterns, formula candidates, structures, and spectra.
Biochemistry
Calculate biomolecule precursors, fragments, modifications, and polymers.
- RNA Molecular Weight CalculatorCalculate RNA molecular weight from a sequence or length. Choose the 5' end and get the formula, g/mol, and picomoles per microgram.
- DNA Molecular Weight CalculatorCalculate DNA molecular weight for an oligo, PCR product, or plasmid. Enter a sequence or length and get g/mol, GC content, and picomoles per microgram.
- Protein Molecular Weight CalculatorCalculate protein or peptide molecular weight from a one-letter sequence. Get g/mol, kDa, monoisotopic mass, formula, and the extinction coefficient at 280 nm.
Applied Chemistry & Education
Use chemistry in pool treatment and education workflows.
- This topic's calculators are held behind their scientific-data or release gate.