The contribution margin formula
Contribution margin is the amount each unit sold contributes toward covering fixed costs and, once those are covered, profit. Per unit it is contribution margin = price − variable cost, and as a percentage the contribution margin ratio = contribution margin ÷ price × 100. Variable costs are the per-unit expenses that rise with each sale — materials, packaging, and shipping. The higher the contribution margin, the fewer units you need to cover fixed costs and turn a profit. Divide fixed costs by this figure and you get the volume the break-even calculator reports.
How to use this calculator
Enter the price per unit you charge and the variable cost per unit to produce and deliver it. The tool returns the contribution margin in dollars and the contribution margin ratio as a percentage. This figure is the building block of break-even analysis: divide fixed costs by the contribution margin to find how many units you must sell. The gross profit margin calculator gives the same idea at the whole-business level.
Worked example
At a $50 price with $30 of variable cost: contribution margin = 50 − 30 = $20.00, a ratio of 40%. Cutting variable cost or raising price both widen the margin:
| Price | Variable cost | Contribution margin |
|---|---|---|
| $50 | $35 | $15.00 (30%) |
| $50 | $30 | $20.00 (40%) |
| $60 | $30 | $30.00 (50%) |
These figures are an estimate for general information only and are not financial advice; consult a qualified professional before making money decisions. If margin is thin, revisit pricing with the markup calculator.
Frequently asked questions
- How do I calculate contribution margin?
- Subtract the variable cost per unit from the price per unit. For a $50 price and $30 variable cost, the contribution margin is $20.00 per unit.
- What is the contribution margin on a $50 price and $30 cost?
- It is $20.00 per unit, a contribution margin ratio of 40%. Each sale contributes $20 toward fixed costs and profit.
- What is the contribution margin ratio?
- It is the contribution margin divided by the price, expressed as a percentage. It shows what share of each sales dollar is left after variable costs.
- How is contribution margin used?
- It drives break-even analysis. Divide total fixed costs by the contribution margin per unit to find how many units you must sell to break even.
- Is contribution margin the same as gross profit?
- No. Contribution margin subtracts only variable costs, while gross profit subtracts everything in cost of goods sold, which can include fixed production costs like factory rent. The two match only when every production cost varies with volume.