Break-even analysis is useful when calculating risk in business planning. It is based on the concept that there are fixed and variable costs.
If a company manufactures computers, the rent on the factory could be thought of as a fixed cost. It needs to be paid even if no computers are produced. However, the components that go into the computer could be thought of as variable costs. They increase with each computer that is produced. Each sold computer contributes to cover fixed costs or make a profit. When enough computers are sold to coves all the fixed costs, then the company is said to be at a break-even point. If more computers are manufactured and sold, there is a profit. If less are manufactured and sold, there is a loss.