Stoichiometry Calculator
Product moles and mass from reactant amounts and mole ratio.
Enter your values
Enter the reactant mass in g.
Enter the reactant molar mass in g/mol.
Enter the reactant coefficient you are working with.
Enter the product coefficient you are working with.
Enter the product molar mass in g/mol.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Moles of product
- 0.25 mol
- Mass of product
- 14.625 g
- Moles of reactant used
- 0.25 mol
Quick answer
Moles of product = moles of reactant x (product coefficient / reactant coefficient).
n_product = n_reactant x (coeff_product/coeff_reactant)
At a glance
| What it does | Product moles and mass from reactant amounts and mole ratio. |
|---|---|
| Category | Science |
| Inputs needed | Reactant mass, Reactant molar mass, Reactant coefficient, Product coefficient, Product molar mass |
| Main output | Moles of product |
| Formula | n_product = n_reactant x (coeff_product/coeff_reactant) |
| Cost | Free — no sign-up, no download |
How to use the Stoichiometry Calculator
- 1Enter the mass and molar mass of your starting reactant.
- 2Enter the coefficients of the reactant and product from the balanced equation.
- 3Enter the product's molar mass to see the mass of product formed.
Inputs explained
- Reactant mass(g)
- Enter the reactant mass in g.
- Reactant molar mass(g/mol)
- Enter the reactant molar mass in g/mol.
- Reactant coefficient
- Enter the reactant coefficient you are working with.
- Product coefficient
- Enter the product coefficient you are working with.
- Product molar mass(g/mol)
- Enter the product molar mass in g/mol.
Worked example
Using the values the calculator loads with:
Inputs
- Reactant mass10 g
- Reactant molar mass40 g/mol
- Reactant coefficient1
- Product coefficient1
- Product molar mass58.5 g/mol
Results
- Moles of product0.25 mol
- Mass of product14.625 g
- Moles of reactant used0.25 mol
Frequently asked questions
What if I have two reactants?
Calculate the product amount from each reactant separately — the smaller value identifies the limiting reagent.
Why do coefficients matter?
They set the mole ratio between reactant and product as required by the balanced chemical equation.
What do I need to enter into the Stoichiometry Calculator?
Just 5 values: reactant mass, reactant molar mass, reactant coefficient, product coefficient, product molar mass. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Stoichiometry Calculator work out the answer?
Moles of product = moles of reactant x (product coefficient / reactant coefficient). It applies the formula n_product = n_reactant x (coeff_product/coeff_reactant) and shows the working so you can check each step by hand.
Is the Stoichiometry Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.