The break-even analysis determines the volume of sales at which revenues and costs are equal, known as the break-even point. The break-even point can be calculated in terms of either physical units or money value of sales. It is the level of sales where total revenues equal total costs, resulting in no profit or loss. The margin of safety is the amount of sales over the break-even point, indicating how much sales can decrease before the firm loses money. Break-even analysis is useful for profit planning, capacity expansion decisions, and determining whether to make or buy a product.