The Business Calc

Contribution Margin Calculator

Contribution margin is selling price minus variable cost per unit — what each sale leaves over to pay fixed costs and profit. Enter both to get it in dollars and as a ratio.

Updated · Standard cost-accounting formulas, shown in full below.

Try an example
Per-unit costs only — not rent or salaries.
    Each sale contributes $20.00

    toward fixed costs and profit — 40.0% of what you charge.

    $50.00 Selling price $30.00 Cost per unit $20.00 Kept per sale

    At this margin it takes 50 sales to cover every $1,000 of fixed costs you carry.

    Margin ratio 40.0%
    Goes to costs 60.0%

    If something changed

    • Price up 10% to $55.00 $25.00 a sale
    • Unit cost down 10% to $27.00 $23.00 a sale

    Contribution margin breakdown

    Where every dollar of the price goes
    $30.00 of every $50.00 sale leaves again immediately to pay for that unit. The remaining $20.00 is all you have to cover rent, salaries and everything else.

    What your margin means

    • Every sale leaves you $20.00 — 40.0% of the price — once its own costs are paid.
    • Every $1,000 of fixed costs you carry takes 50 sales to cover at this margin.
    • A 10% price rise would lift contribution to $25.00 a sale — margin responds much faster than price does.

    Contribution margin formula

    Formula and worked example
    contribution margin = selling price − variable cost per unit contribution margin ratio = contribution margin ÷ selling price

    A negative result means variable cost exceeds the price. The calculator shows it rather than treating it as an error — knowing you lose money on every unit is the useful answer.

    Contribution margin isn't quite gross profit: gross profit subtracts cost of goods sold, which often bundles in some fixed overhead. This subtracts only truly variable costs, which is what makes it the right input for break-even.

    Worked example

    Selling price
    $50
    Variable cost
    $30
    Contribution
    $20 · 40%
    Against $10,000 fixed costs
    500 units to break even

    Contribution margin FAQ

    What is contribution margin, in plain terms?

    It's what's left from one sale after paying the variable cost of that specific sale — the amount left over to go toward fixed costs and, eventually, profit. It says nothing yet about whether the business as a whole is profitable.

    What counts as variable cost here?

    Only costs that scale directly with each unit: materials, direct labor per unit, packaging, per-unit shipping or payment-processing fees. Fixed costs like rent or salaries are deliberately excluded from this calculation.

    Is a negative contribution margin always a sign to stop selling a product?

    Usually yes for the long run — every sale actively loses money, and no amount of volume fixes that. In the short term there can be strategic reasons to accept it temporarily, such as clearing inventory or entering a market, but it isn't sustainable.

    How is the contribution margin ratio different from the dollar amount?

    The dollar amount is useful per unit. The ratio (margin divided by price) is useful for comparing products with very different price points, and for estimating how much of each additional sales dollar becomes profit.

    Is contribution margin the same as gross profit?

    They're closely related but not identical. Gross profit subtracts cost of goods sold, which often includes some fixed production overhead. Contribution margin subtracts only truly variable costs, which is what makes it the right input for break-even analysis.

    Related calculators

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    Next step Break-Even Calculator Turn this per-sale margin into the sales volume your business needs.