What break-even measures
This guide uses a U.S. small business context; costs and applicable requirements vary by business and location.
Break-even is the sales level at which the revenue and costs included in a model are equal. It is a planning estimate, not a promise of demand or a substitute for cash in the bank. The SBA’s single-product formula divides fixed costs by the difference between selling price and variable cost per unit.
Define the period first. A monthly sales target should use monthly fixed costs and a monthly view of variable costs. Be clear about whether the model includes owner compensation, financing costs, taxes or other obligations; a result that omits a material cost can look safer than the business actually is.
Separate fixed and variable costs
Fixed costs in a simple model do not change with the number of units sold within the relevant range and period. Rent under an existing lease is a common example. Variable costs change with output or sales, such as materials, per-order packaging and transaction charges. Some costs have both components, such as a service with a monthly minimum plus a per-transaction fee.
- List recurring fixed expenses for the same period as the target.
- Estimate the incremental materials, labor, fulfillment and payment costs of one unit.
- Separate mixed costs into fixed and variable components where practical.
- Include returns, discounts and waste in assumptions when they are material.
- Check whether costs jump at a capacity threshold.
These categories are models, not permanent labels: a business may need another machine or shift if volume grows, turning a seemingly fixed amount into a step change.
Calculate a simple example
Illustration only: suppose a shop has $3,000 of fixed monthly costs, sells one product for $50 per unit, and incurs $20 of variable cost per unit. Each sale contributes $30 toward fixed costs. Dividing $3,000 by $30 gives a break-even volume of 100 units in that month.
At 100 units, modeled revenue is $5,000 and modeled costs are $3,000 fixed plus $2,000 variable. Both equal $5,000. At 101 units, the simplified model shows $30 above those modeled costs. The example is not a forecast and excludes any costs not included in the assumptions.
Test the margin and the sales mix
If the selling price does not exceed variable cost, each sale fails to contribute a positive amount toward fixed costs; dividing by zero or a negative contribution does not produce a useful positive break-even target. A higher price can improve contribution, but may also reduce demand. A lower cost may require a change in supplier, materials or service level.
For several products, a single-unit calculation can mislead because each product has a different contribution. Model the expected mix and revisit it when the mix changes. Discounts, wholesale channels, shipping and returns can change actual contribution per sale.
Turn the estimate into a decision
Compare the required volume with realistic capacity and the sales the business can plausibly generate. Run a lower-volume case and a higher-cost case, not just a best case. Review actual results against assumptions and investigate the differences before using the model for a major commitment.
Break-even is about the included revenue and costs, while cash availability also depends on when customers pay and bills fall due. A business may need funding before it reaches its target even if the model suggests long-run viability. Use the calculation alongside a cash forecast and seek accounting help where the decision warrants it.
Document assumptions for the next review
Write the model in a form another person can follow: the period, unit definition, sales price, expected variable costs and fixed cost total should all be visible. If one order contains several items, decide whether the unit is an item or an order and use that definition consistently. Payment fees and shipping costs may behave differently for each. Record the source and date of each estimate, especially supplier quotes that can expire. As actual orders arrive, compare realized prices and costs with the model. A small difference in contribution per unit can change the number of sales needed to cover fixed costs. Repeat the calculation after a material price, supplier or capacity change rather than treating the original target as permanent.
Before using the target to commit to a lease or equipment purchase, test whether the required sales fit available capacity. Record which costs would increase at a higher volume and rerun the model when supplier prices or the sales mix change.