Contribution Margin Calculator
What one more sale contributes once its variable costs are paid.
Contribution margin is price minus variable cost — the money one additional sale contributes toward fixed costs, and then, once those are covered, straight to profit. It sits behind almost every operating decision a founder makes: whether to accept a discounted order, which product the sales team should push this quarter, whether a channel is worth its cost per customer. Gross margin describes the business as a whole; contribution margin describes the next unit. Enter price and variable cost for the per-unit figure and the ratio, then add volume and fixed costs for total contribution, break-even and your margin of safety.
Reading contribution margin like an operator, not an accountant
- Variable costs are the ones that exist only because a sale happened: materials, payment fees, shipping, sales commission, and per-customer support or API cost.
- The ratio — contribution ÷ price — is what makes different products comparable. A $19 add-on at 90% can be worth more per marketing dollar than a $500 product at 20%.
- Use it for accept-or-decline calls: as long as a one-off order clears its variable cost and does not displace full-price work, it adds real contribution even at a discount.
- Sales commission belongs in variable cost. Teams that leave it out consistently overestimate what an aggressively discounted deal actually contributes once everyone has been paid.
- Shift the mix toward high-ratio products before chasing more volume — changing what you sell moves profit without adding a single customer or another dollar of spend.
- If contribution margin is negative, every extra sale makes things worse. Fix price or per-unit cost first; no marketing budget survives a unit that loses money on delivery.
Example output
Price / variable cost / volume / fixed costs: Price $149 · variable cost $32 · 400 units per month · $28,000 fixed costs
Contribution margin: $117.00 per unit Contribution margin ratio: 78.5% — 78.5¢ of every sales dollar is left to cover fixed costs and profit. At 400 units/month: total contribution $46,800. Break-even: 240 units/month covers $28,000 of fixed costs. Operating profit at 400 units: $18,800/month. Margin of safety: 160 units (40.0% above break-even).
Frequently asked questions
- What's the difference between contribution margin and gross margin?
- Gross margin subtracts all cost of goods sold, including production costs that stay put regardless of volume. Contribution margin subtracts only the costs that move with each unit. Gross margin reports on a period that already happened; contribution margin predicts what happens if you sell one more, which is why it drives operating decisions.
- How does contribution margin relate to break-even?
- Break-even units = fixed costs ÷ contribution margin per unit. Every sale pushes its contribution onto the fixed-cost pile, and when the pile is covered you have broken even — each sale after that contributes profit. It is also why raising price or cutting variable cost lowers your break-even from both directions at once.
- Should I ever accept an order below my normal price?
- If it clears variable cost, does not cannibalise full-price demand, and does not reset what that customer expects to pay next time, then yes — the contribution is real money against fixed costs. Below variable cost it is a donation that you also have to spend time delivering.
- Why is this free — what's the catch?
- No catch and no signup. This tool is funded by EaseClaw, an AI agent that finds people publicly asking for what you sell and drafts your replies. If the free tool is useful, some people try the free trial. That's the whole business model.