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Empirical Formula Calculator

Find the empirical (and molecular) formula from mass percentages or experimental masses.

Related tools

All Chemistry tools →
Chemical Equation BalancerBalance any chemical equation instantly by solving the element matrix exactly — even tricky redox reactions.Limiting Reactant CalculatorDetermine which reactant runs out first from the amounts you have and the balanced equation's mole ratios.Molar Mass CalculatorCompute the molar mass of any chemical formula, with per-element composition.Mole/Gram/Particle ConverterConvert between moles, grams and number of particles using molar mass and Avogadro's number.Interactive Periodic TableExplore the 118 elements — click any element for its atomic number, mass, category and properties.Stoichiometry CalculatorConvert between grams, moles and liters at STP across a balanced equation using mole ratios.Theoretical Yield CalculatorFind the theoretical yield of a product from reactant amounts, plus the limiting reactant and percent yield.Dilution calculator (C1V1 = C2V2)Find the final volume needed to dilute a solution to a target concentration.

Open Empirical Formula Calculator and you get an answer straight away, with no account to create. It sits under Chemistry in our catalogue, alongside Chemical Equation Balancer and Limiting Reactant Calculator.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What is Empirical Formula Calculator?

Find the empirical (and molecular) formula from mass percentages or experimental masses.

When would I actually use this?

Preparing a solution at a stated concentration, working out how much of a reagent a reaction needs, and converting between mass, moles and volume.

What is the most common mistake?

Confusing molarity with molality. One is per litre of solution and the other per kilogram of solvent; they diverge as concentration rises, and only one of them is temperature-independent.

Is there a tool for the next step?

Limiting Reactant Calculator is the closest one after this: Determine which reactant runs out first from the amounts you have and the balanced equation's mole ratios.

What else is worth having open alongside it?

Molar Mass Calculator and Mole/Gram/Particle Converter — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

Atomic masses are the IUPAC standard values. Results assume ideal behaviour and standard conditions unless the tool says otherwise — real solutions deviate, and lab work needs lab measurement.

Further reading

All guides →
ExplainerMolarity Is per Litre of Solution, Not per Litre of Water0.5 mol in 2 litres is 0.25 mol/L. The two litres have to be the finished solution — adding solute to two litres of water gives something else, and the label will be wrong.How-toHow to Solve Stoichiometry Problems: Grams to Moles to Ratio to GramsEvery problem in the chapter is the same four moves. The mole ratio is the hinge, and it is the step students lose — worked here end to end, limiting reactant and percent yield included.How-toHow to Calculate Molar Mass, Including Parentheses and HydratesMultiply each atomic weight by its subscript and add. The only three places the arithmetic goes wrong are a subscript after a closing bracket, the hydrate dot, and a capital letter typed as a lowercase one.ExplainerAn Absorbance of Two Means One Per Cent of the Light Gets Through6,220 M⁻¹cm⁻¹ at 100 µM through 1 cm gives A = 0.622, and 23.9 % of the light emerges. Double the path length and A doubles to 1.244 — the scale is logarithmic, and that is where it breaks.ExplainerThe Same Burette Reading Gives Two Different Concentrations24.80 mL of 0.1 M titrant into 25.00 mL of analyte gives 0.0992 M — or 0.0496 M if the analyte releases two protons. The stoichiometry is typed, not measured.ExplainerEighty Per Cent Five Times Over Leaves a Third8 grams obtained where 10 were possible is an 80 % yield. Chain five such steps and 32.8 % of the starting material reaches the end — which is why a long synthesis is judged step by step.