Calculation note
Break-even analysis is a simple management-accounting tool: it separates fixed costs from per-unit contribution so a price or launch plan can be checked before money is committed.
Contribution margin is the useful unit number
Revenue alone does not cover fixed costs. Each sale first has to pay its own variable cost, and only the remaining contribution can help recover fixed costs. That is why the calculator makes contribution margin visible in the result support text.
Break-even is not the same as success
Breaking even means the entered fixed costs are covered under the stated assumptions. It does not include cash timing, inventory risk, taxes, owner wages, customer acquisition volatility or whether enough demand exists at the chosen price.
Target profit changes the question
Adding target profit turns the calculation from “How many sales cover costs?” into “How many sales cover costs and leave this profit?” The same contribution margin formula handles both, but the business decision is different.