Contribution margin per unit
Selling price minus variable cost gives contribution margin per unit. Divide fixed costs by that amount to find the exact break-even quantity. When only whole units can be sold, round up to the next whole unit.
Classifying costs matters
Fixed costs stay unchanged within the modeled activity range, while variable costs change with each unit. Real costs can be mixed, stepped, capacity-limited, discounted, or affected by returns and waste. A different classification changes the answer.
One product and one price
This version assumes every unit has the same price and variable cost and every unit is sold. Multiple products require a stable sales mix or a separate contribution analysis. Taxes, financing costs, timing, inventory, and cash flow are not modeled.
A worked whole-unit example
With $10,000 of fixed costs, a $50 selling price, and $30 variable cost per unit, contribution is $20 per unit. Exact break-even is $10,000 ÷ $20, or 500 units, corresponding to $25,000 of modeled revenue. If the exact result is 500.2 and partial units cannot be sold, the practical threshold is 501 whole units.
Stress-test price, cost, and volume
A discount reduces contribution unless variable cost falls too. A supplier increase raises the required unit count, while a capacity threshold can add a new block of fixed cost. Run downside and upside cases instead of relying on one precise number, and compare the resulting whole-unit target with realistic demand and production capacity.
Break-even is not a cash-flow date
The formula describes modeled revenue and cost, not when cash arrives. Inventory, payroll, rent, tax, deposits, customer payment terms, and loan payments can create a cash shortfall even when cumulative accounting revenue reaches the break-even amount. Build a separate cash timeline for timing decisions.
Use the Margin and Markup Calculator to keep the percentage baselines visible. The small-business pricing and profit guide connects unit cost, realized price, contribution, discounts, commissions, transaction tax, volume, and cash timing.
This is a simplified planning calculation, not accounting, pricing, tax, or financial advice. Validate cost behavior and assumptions before relying on a break-even target.