The formula, in plain language
Break-even units = Fixed costs / (Price per unit − Variable cost per unit)
The denominator — price minus variable cost — is the contribution margin: how much each sale contributes toward paying off fixed costs before anything becomes profit.
Worked example
Suppose your fixed costs are $50,000 per period, you sell each unit for $25, and each unit costs $15 in materials and variable costs to produce:
- Contribution margin: $25 − $15 = $10 per unit
- Break-even units: $50,000 ÷ $10 = 5,000 units
- Break-even revenue: 5,000 × $25 = $125,000
Selling fewer than 5,000 units means a loss; selling more means profit.