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Contribution Margin Calculator

Revenue minus variable cost.

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What does Contribution Margin mean?

Contribution margin — also called unit contribution — is the amount remaining from sales revenue after deducting variable costs. It represents how much each unit sold contributes toward covering fixed costs and generating profit. A higher contribution margin means each sale is more profitable, giving the business greater flexibility to cover overhead and invest in growth.

How to calculate Contribution Margin

Contribution margin is a subtraction, not a percentage trick: take what a unit sells for and remove only the costs that move with volume. Whatever is left over is what that sale contributes to fixed costs and profit. The calculator above works in dollars only — there is no percentage to enter, because the ratio is an output, not an input.

Contribution margin formula

  • Per unit: contribution margin per unit = price per unit − variable cost per unit
  • Total: total contribution margin = total revenue − total variable costs
  • Ratio: contribution margin ratio = (contribution margin ÷ revenue) × 100 — per unit that is (contribution margin per unit ÷ price per unit) × 100
  • Break-even units: fixed costs ÷ contribution margin per unit

The per-unit and total versions always agree: multiply the per-unit margin by units sold and you get the total contribution margin, so the ratio is the same either way. Only the ratio is expressed as a percent — it comes out of the division, which is why the calculator asks for prices and costs rather than a margin percentage.

Worked example

A workshop sells a chair for $150. Wood, hardware, finishing labor and shipping come to $60 per chair. Rent, salaries and insurance add up to $18,000 a month.

  • Step 1 — contribution margin per unit: $150 − $60 = $90 per chair. Each chair sold puts $90 toward the monthly overhead.
  • Step 2 — contribution margin ratio: $90 ÷ $150 = 0.6, and 0.6 × 100 = 60%. Sixty cents of every sales dollar survives the variable costs.
  • Step 3 — break-even units: $18,000 ÷ $90 = 200 chairs a month. Chair 201 is the first one whose $90 lands in profit.
  • Step 4 — check it on the total: sell 500 chairs and revenue is 500 × $150 = $75,000 while variable costs are 500 × $60 = $30,000. Total contribution margin is $75,000 − $30,000 = $45,000, which is also 500 × $90 — and $45,000 ÷ $75,000 × 100 is still 60%.

Enter 150, 60 and 18,000 in the three fields above to reproduce every line of this example, then swap in your own price and costs.

FAQ

Find contribution margin by subtracting variable costs from revenue. For one unit: contribution margin per unit = price per unit − variable cost per unit. For the whole business or a product line: total contribution margin = total revenue − total variable costs. Start from the selling price on your invoice, add up only the costs that rise and fall with volume (materials, direct labor, packaging, shipping, commissions, payment fees), and subtract them. Leave out rent, salaries and insurance — those are fixed costs and belong in the break-even step, not in the contribution margin itself.

The contribution margin per unit formula — also called unit contribution — is: contribution margin per unit = selling price per unit − variable cost per unit. For example, if you sell a product for $75 and the variable costs are $30, the contribution margin per unit is $45, meaning each unit sold contributes $45 toward covering fixed costs and profit. Multiply the per-unit figure by the number of units sold to get the total contribution margin, or divide it by the selling price and multiply by 100 for the contribution margin ratio.

Contribution margin ratio = (contribution margin ÷ revenue) × 100. Per unit, that is (contribution margin per unit ÷ price per unit) × 100. A $90 margin on a $150 price gives 90 ÷ 150 = 0.6, or 60%. The ratio is what the calculator reports as a percentage — you never type a percentage in, you only enter prices and costs.

A "good" contribution margin ratio varies by industry. Manufacturing companies often target 30–40%, while software and service businesses may see ratios of 70–90% due to lower variable costs. The key is that the margin must be high enough to cover fixed costs and leave a profit.

Contribution margin only subtracts variable costs from revenue, showing how much each unit contributes to covering fixed costs. Profit margin subtracts all costs (both variable and fixed) from revenue, showing the overall profitability of the business. Contribution margin is a per-unit metric, while profit margin is typically calculated on total revenue.

Yes. A negative contribution margin means the variable cost per unit exceeds the selling price — you lose money on every unit sold. In this situation, selling more units only increases losses, and break-even is unreachable at that price. You need to either raise prices or reduce variable costs before the product can become viable.

Contribution margin shows the minimum price at which a product is worth selling. If the contribution margin is positive, each additional unit sold helps cover fixed costs. This insight helps businesses set prices, evaluate discount strategies, and decide which products to prioritize in their product mix.

Variable costs change in proportion to production or sales volume. Common examples include raw materials, direct labor, packaging, shipping, sales commissions, and payment processing fees. Costs like rent, salaries, and insurance are fixed costs and are not included in the contribution margin calculation.

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