Science & Engineering

Stoichiometry Calculator

Converts moles of reactant A into moles of product B using the balanced mole ratio: B = A x (coefficient of B / coefficient of A). Enter 2 mol of A with coefficient 1 for A and 2 for B to get 4 mol of B.

What this calculator does

The Stoichiometry Calculator estimates your result instantly from the values you enter, using standard science & engineering formulas. Converts moles of reactant A into moles of product B using the balanced mole ratio: B = A x (coefficient of B / coefficient of A). Enter 2 mol of A with coefficient 1 for A and 2 for B to get 4 mol of B. Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate rather than a certified or official figure.

Stoichiometry Calculator

Result

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Moles of Product B

About Stoichiometry Calculator

This stoichiometry tool applies the mole ratio from a balanced equation. Given the moles of reactant A and the stoichiometric coefficients of A and B, it returns the moles of product B as nB = nA × cB / cA. Use it to scale a reaction from a known amount of one species to another.

Formula & Mathematical Calculation

Moles of Product B = f(Moles of Reactant A, Coefficient of A, Coefficient of B)

Calculated according to standard science formulas implemented in the calculator core.

Calculation Example

With 2 mol of reactant A, coefficient of A = 1 and coefficient of B = 2: nB = 2 × 2 / 1. The Moles of Product B box shows 4 mol, and the note reads Using the mole ratio 2:1, 2 mol of A yields 4 mol of B.

Key Benefits

  • Converts a known amount of reactant A into moles of product B
  • Uses the exact balanced-equation coefficients you enter
  • Rounds the result to four decimal places in moles
  • Shows the applied mole ratio in the explanation

How to Use this Calculator

  1. Enter moles of reactant A
    Type the known number of moles of A into the Moles of Reactant A field.
  2. Enter the coefficient of A
    Provide A's coefficient from the balanced equation in the Coefficient of A field.
  3. Enter the coefficient of B
    Provide B's coefficient in the Coefficient of B field.
  4. Calculate
    Click Calculate and read the Moles of Product B box.

Assumptions & Limitations

What the calculation assumes

  • Every value you enter is treated as an exact, known amount.
  • Any rate or interval you enter is assumed to hold for the whole period unless the form asks for it separately.
  • Results use standard published formulas and account only for the values entered above.
  • Rounding is applied for display; the underlying calculation uses your full precision.
  • Results are returned in the same units you enter, unless the tool states the output unit.

What it does not cover

  • Stoichiometry Calculator produces a calculated result for reference and learning, not a certified or official measurement.
  • Real-world outcomes differ when tolerances, rounding rules or local standards apply.
  • Definitions and standards vary by region and change over time; verify the convention that applies to your case.
  • Figures are only as accurate as the inputs you supply — check them before acting on the result.
  • For work where the result carries real consequences, confirm it against an authoritative source.

Frequently Asked Questions

It multiplies moles of A by the ratio cB/cA, so moles of B = moles of A x coefficient of B / coefficient of A.

The coefficient of A is the divisor in the mole ratio, so if it is 0 or less the tool shows an error asking for a value greater than 0.

Yes, the coefficient fields accept any positive value including decimals, though balanced equations usually use whole numbers.

No. You must supply the coefficients from an already balanced equation; the tool only applies the mole ratio.

Free to use, no account needed. Calculations run in your browser, so nothing you type is sent to a server. Results are estimates — how we build and check our calculators.