Break-Even & Contribution Margin

How to use it

Enter your price, the cost of producing one more unit, and your fixed costs for the month. The result is how many units you must sell before you make any profit at all, how far sales could fall before you get there, and what it takes to hit a profit target.

Where the number comes from

• Contribution per unit is price minus variable cost — what one extra sale leaves behind after the cost of making it.
• Contribution margin expresses that as a percentage of price.
• Break-even volume is fixed costs divided by contribution per unit. Every unit up to that point is paying down the fixed cost base.
• Units for a target profit adds the target to fixed costs before dividing, since profit behaves exactly like another fixed cost you have chosen to cover.
• Margin of safety is how far current sales sit above break-even, as a percentage of current sales.
• Operating leverage is total contribution divided by profit, and it tells you how violently profit reacts to a change in volume.

What goes wrong

The part most calculators leave out.

• The split between fixed and variable is rarely clean. Costs described as fixed are usually fixed only within a range — sell three times as much and you need another shift, another warehouse, another manager.
• This assumes one product at one price. A business with a product mix has a break-even that shifts whenever the mix does, even at constant total volume.
• It also assumes price does not change with volume. If you discount to sell more, contribution falls exactly as volume rises and break-even moves away from you rather than toward you.
• Break-even is measured in profit, not cash. A profitable month can still be a cash-negative one if customers pay late — that is a different calculation entirely.
• Variable cost must include everything that scales: materials, shipping, payment processing, commission. Payment fees in particular are routinely left out and are genuinely variable.

Questions

What is the difference between contribution margin and gross margin?

They are close but not identical. Gross margin uses cost of goods sold as reported, which often contains some fixed production overhead. Contribution margin uses only genuinely variable costs. For break-even work you want contribution.

Is a high operating leverage good or bad?

Both, depending on which direction sales move. High leverage means a heavy fixed base and thin variable costs, so profit rises fast above break-even and falls just as fast below it. It rewards growth and punishes downturns.

Should payment processing fees count as variable cost?

Yes. They scale directly with sales and are one of the most commonly omitted variable costs. Leaving them out flatters contribution and understates the volume you actually need.

Does anything I type get sent anywhere?

No. The whole calculation runs in your browser. Nothing is transmitted, stored, or logged, and there is no account to create.