This assumes a single product (or a consistent average price and cost across your product mix) and constant fixed costs over the period — real businesses often sell multiple products with different margins, which this simple version doesn't separate out.
Your Cost Structure
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Rent, salaries, insurance, loan payments — costs that don't change with how much you sell.
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Materials, direct labor, packaging — cost that scales with each unit.
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Go Further Optional
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See your margin of safety above break-even.