Contribution Margin Explained
Contribution margin is the amount each sale contributes to covering your fixed costs — and then to profit.
What contribution margin means
Contribution margin is what's left from the price of a sale after subtracting the variable cost of that sale. Once your fixed costs are paid for the month, every dollar of contribution margin becomes profit.
Why it matters for small business
It helps you compare products honestly. A high-priced item with high variable cost may contribute less than a cheaper one with low variable cost. It's also the core input to your break-even point.
Simple formula
Contribution Margin (%) = (Contribution Margin ÷ Price) × 100
Practical example
A handmade soap sells for $8. The soap base, fragrance, packaging, and per-unit shipping add up to $3 of variable cost.
Contribution Margin % = ($5 ÷ $8) × 100 = 62.5%
If fixed costs for the month are $2,000, the maker needs 400 soaps sold to break even ($2,000 ÷ $5).
Practical interpretation
- Higher contribution margin = fewer sales needed to be profitable.
- Use contribution margin to rank products and prioritise the ones that pull their weight.
- Don't confuse a high price with a high contribution — variable cost matters just as much.
Common mistakes
- Treating fixed costs as variable. Rent doesn't change because you sold one more unit.
- Ignoring shipping/transaction fees. Payment processor fees are real variable costs per sale.
Need to calculate this? Visit SME Finance Helper.
This article is for educational and planning purposes only. It is not accounting, tax, legal, investment, or financial advice.