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Chemistry calculator

A set of common chemistry calculations in one place: pH and pOH, molarity, the ideal gas law, dilution, thermodynamics and molar mass.

How it works Report a problem

Chemistry calculatorChemistry

pH · Molarity · Ideal Gas · Dilution · Thermodynamics

pH = −log₁₀[H⁺]  |  pOH = −log₁₀[OH⁻]  |  pH + pOH = 14 (at 25°C)

Chemistry homework and lab work recycle the same core calculations: moles from mass, concentration from moles and volume, dilutions, and the gas laws. This general chemistry calculator gathers those everyday sums in one place with the formulas applied correctly.

How to use this calculator

  • Choose the calculation you need (moles, concentration, dilution or a gas law).
  • Enter your values with their units.
  • Press calculate to see the result and the formula used.

Units decide more answers than formulas do

Most chemistry errors are unit errors: millilitres where litres belong, grams where kilograms belong in a physics crossover, Celsius where kelvin is required. The habit this calculator is built around is converting first, calculating second, and sanity-checking the size of every answer against the experiment.

Frequently asked questions

What calculations does a chemistry calculator cover?
The everyday set: moles and molar mass, concentration and dilution, percentage composition, gas laws and simple stoichiometry.
How do I calculate moles from mass?
Moles = mass divided by molar mass. Find the molar mass by adding the atomic masses in the formula, in grams per mole.
Why does my answer look off by 1,000?
Almost always a litre/millilitre or gram/kilogram slip. Chemistry's standard units are litres and grams in most school and lab formulas; check those first.