Business math, made visible
Break-even calculator
Break-even calculator
Find the sales quantity that covers your costs.
Inputs stay in this browser. Results use your entries and the formula below.
Use this break-even calculator to find the quantity and sales revenue needed to cover fixed and variable costs. Enter fixed costs for one period, plus the selling price and variable cost for one unit. The tool reports the exact quantity, the next whole-unit quantity when needed, and the associated revenue. It follows the single-product method described by the Small Business Administration. Keep your sales unit and accounting period consistent before interpreting the result as a business target.
Worked example
| Source item | Published value |
|---|---|
| Fixed costs | $100 |
| Selling price per pound | $1.00 |
| Variable cost per pound | $.50 |
| Break-even volume | 200 pounds |
| Total sales at break-even | $200 |
The NOAA-hosted seafood retail example uses these figures. Here a unit is a pound. Each pound contributes $.50 toward fixed costs, so $100 / $.50 = 200 pounds. Source: NOAA repository: seafood retail break-even example, page 117.
How it works
Break-even units = fixed costs / (selling price per unit - variable cost per unit)
Formula basis: SBA: break-even and contribution formulas. Ratios are converted to percentages for display. Intermediate values retain full calculation precision; displayed amounts are rounded.
Choose a period before entering costs
Fixed costs belong to the same period as the sales quantity you want to evaluate. Enter monthly costs for a monthly quantity or annual costs for an annual quantity. A longer period with more fixed costs will change the answer. Variable costs are entered per unit, not as a total for that period. Mixing total variable costs with a per-unit price would make the denominator meaningless.
Understand the contribution denominator
Selling price minus variable cost is the amount available from each sale to cover fixed costs. The calculator requires that difference to be positive. If the difference is zero, extra sales contribute nothing toward fixed costs. If it is negative, selling additional units makes the modeled loss larger. The single-product formula cannot provide a useful positive break-even target in those cases.
Use the exact and whole-unit results
The exact quantity is the mathematical threshold. If the product is sold only in whole pieces, the calculator also rounds the quantity upward and shows sales revenue at that quantity. For divisible units such as pounds or service hours, the exact quantity may be more useful. The exact revenue threshold and rounded sales target are labeled separately. Neither result checks whether demand or production capacity can support the target.
Use the formula in a spreadsheet
With fixed costs in A1, selling price in B1, and variable cost in C1, use =A1/(B1-C1). For indivisible products, use =ROUNDUP(A1/(B1-C1),0). Multiply the chosen quantity by B1 to get the corresponding sales revenue.
Frequently asked questions
What is the break-even formula?
Divide fixed costs by selling price per unit minus variable cost per unit. The denominator is the contribution from each unit sold.
How do I calculate break-even in Excel?
Use =A1/(B1-C1) with fixed costs, price, and variable cost in those cells. Check that the price exceeds variable cost before dividing.
Why does the tool round units up?
Whole products must cover all fixed costs. Rounding a fractional requirement down would leave part of the fixed cost uncovered.
Can I calculate break-even sales dollars?
Yes. The tool multiplies the exact quantity by selling price and separately reports revenue at the whole-unit target.
What if variable cost equals selling price?
This model cannot calculate a useful break-even target because each sale contributes nothing toward positive fixed costs.
Can I use this for several products?
The displayed formula assumes one product or one consistently defined service. A changing product mix requires a separate weighted contribution analysis.
Sources
- SBA: break-even and contribution formulas
- NOAA repository: seafood retail break-even example, page 117
Data as of 2026-10-05. Examples are historical teaching examples, not current prices or market benchmarks. Calculated results are derived from entered values.
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