Break-even analysis finds the value of an input parameter at which an outcome metric reaches a specific threshold — most commonly PW = 0, the breakeven between accept and reject. Equivalent question: “How wrong would my estimate need to be before the answer flips?”
A classic application: a manufacturing project’s profitability depends on the selling price . Compute the price at which PW equals zero. That price is the break-even price. If your actual price is comfortably above it, you have margin to spare; if it’s marginal, the project is risky.
For the simpler cost-volume-profit form (no time-value-of-money), break-even quantity is
where is fixed cost, is selling price per unit, and is variable cost per unit (see Total cost). Above you make money; below, you lose.
For the time-value form: set PW (or AW, or any other metric) equal to the threshold, treat one input as the unknown, and solve. In an engineering project with first cost , annual revenue , annual cost , salvage at year , and MARR :
Solve for the parameter of interest. If solving for : . This is the break-even revenue — the annual revenue required to make the project economically neutral.
Strengths. Answers concrete “what would have to be true” questions. Very useful for scenario planning: “the project pays off if we sell at least 10,000 units/year — is that realistic?” Easy to explain to non-technical stakeholders.
Weaknesses. Only one variable at a time (same as Sensitivity analysis); doesn’t capture variable interdependencies. Doesn’t tell you the probability of being at break-even, only the value where it is. Useful as a planning tool, not a complete risk model.
For the related technique that traces sensitivities rather than thresholds see Sensitivity analysis. For probabilistic risk analysis see decision tree and Expected value (engineering economics). For the broader topic see Risk and uncertainty.