Contribution Margin Calculator
CheckedThe contribution margin calculator shows what each unit contributes after variable costs, as dollars and as a ratio, and the units you need to break even. Free, no sign-up, and the result updates as you type.
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Contribution margin is not gross margin with a longer name. Gross margin subtracts product cost; contribution margin subtracts every cost that only exists because the sale happened — the marketplace fee, the payment charge, the box, the postage. It is the money each sale contributes towards rent, and fixed costs never enter the per-unit number. Allocating a share of the rent to each unit is absorption costing, and it makes low-volume months look unprofitable when they are simply low-volume.
How it's calculated
Contribution margin = price − variable cost per unit Ratio = (price − variable cost) ÷ price × 100 Total = margin × units
LaTeX source
\text{CM} = P - V \qquad \text{CM ratio} = \frac{P - V}{P} \times 100 \qquad \text{Total CM} = (P - V) \times Q Worked examples
A $29.99 product with $17.45 of variable cost
$12.54 per unit, 41.81% ratio
Every sale leaves $12.54 towards fixed costs, a 41.81% contribution margin ratio. At 1,400 units that is $17,556 of total contribution; after $9,000 of fixed costs the operating income is $8,556. Break-even sits at 717.7 units, so roughly half the current volume is pure profit.
The numbers used
- Price per unit
- 29.99
- Variable cost per unit
- 17.45
- Units sold
- 1400
- Fixed costs per period
- 9000
An $80 item with round economics
$32.00 per unit, 40.00% ratio
$32 of contribution on an $80 price is a clean 40% ratio. Five hundred units contribute $16,000, leaving $6,000 after $10,000 of fixed costs. Break-even is 312.5 units — a useful sanity check, because selling 300 in a slow month would put the period into a loss.
The numbers used
- Price per unit
- 80
- Variable cost per unit
- 48
- Units sold
- 500
- Fixed costs per period
- 10000
Questions sellers ask
How do you calculate contribution margin?
Subtract the variable cost of one unit from its selling price. $29.99 − $17.45 is $12.54. Variable means anything that only occurs because that sale happened: product cost, marketplace commission, payment processing, packaging and postage. Rent and salaries are fixed and stay out of it.
What does a 40% contribution margin mean?
Forty cents in every sales dollar is left to cover fixed costs and profit. On an $80 item that is $32 a unit. It also tells you the leverage: once fixed costs are covered, 40% of every extra dollar of revenue drops to operating income, which is why the units after break-even are worth far more than the ones before it.
What's a good contribution margin ratio?
Physical products typically run 25-45%, software far higher because its variable cost is close to zero. What makes a ratio good is whether it clears fixed costs at achievable volume: 30% is comfortable on $5,000 of monthly overheads and hopeless on $50,000. Compare against your break-even units, not against another industry.
How do I calculate contribution margin ratio?
Divide contribution margin per unit by the selling price, then multiply by 100. $12.54 ÷ $29.99 is 41.81%. You can also work it from period totals — total contribution divided by total revenue — which is the version to use for a mixed catalogue where there is no single unit price.
What is a 30% margin on $100?
A 30% margin on a $100 selling price is $30 of margin and $70 of cost. Note the denominator: this is margin, not markup. A 30% markup on a $100 cost would give a $130 price and only a 23.1% margin. Mixing the two is the most common pricing error in retail.
What is the contribution margin ratio?
It is contribution margin expressed as a percentage of revenue rather than in dollars. Its main use is break-even in revenue terms: fixed costs divided by the ratio gives the sales figure you need, without counting units. $12,000 of fixed costs at a 40% ratio means $30,000 of sales to break even.
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