The break-even formula
Break-even units = Fixed Costs ÷ (Price − Variable Cost per Unit). The denominator is your contribution margin — the profit each sale contributes toward covering fixed costs.
Why break-even matters
It converts a cost structure into a concrete sales target: the minimum volume needed to avoid a loss. That makes it a staple of profitability cases and business plans.
Reading the result
If the break-even volume looks unrealistic relative to the market, the economics don't work — a fast, defensible conclusion to reach in an interview.