Break-Even Calculator

Break-even analysis finds the sales volume at which total revenue exactly equals total costs, so the business makes neither profit nor loss. The formula is fixed costs divided by the contribution margin per unit, and the contribution margin is the selling price less the variable cost of making one more item. That margin is what each sale contributes towards covering the overheads you carry whether or not anything sells.

Fixed costs stay the same whatever your output. Rent, business rates, insurance, salaries that are not commission-based, software subscriptions, accountancy fees and equipment leases all sit here. Variable costs move in step with production, covering raw materials, packaging, delivery, sales commission, hourly wages and the electricity a machine draws. A third group is semi-variable, such as a phone bill with line rental plus per-call charges, utilities with a standing charge and usage, or maintenance. Separating the categories properly is the part people get wrong, and treating a variable cost as fixed shifts the break-even point badly. A UK micro-business typically carries £15,000 to £40,000 of fixed costs a year, with the variable side depending entirely on what it sells.

Alongside the unit figure sits a revenue break-even, which is fixed costs divided by the contribution margin ratio, that ratio being the selling price less the variable cost, all divided by the selling price. This version suits a business selling several products at different prices, where an answer in units means little. Sensitivity analysis, meaning adjusting price, costs or volume and watching the answer move, shows how fragile or resilient the margin really is.

A worked example makes the arithmetic concrete. Suppose fixed costs of £20,000 a year covering rent, salaries and insurance, a selling price of £50 per unit and a variable cost of £20 for materials and packaging. The contribution margin is £30 per unit, so break-even is £20,000 divided by £30, which is 667 units. Sell more than that and you are in profit, fewer and you are losing money. At the £50 price, break-even revenue works out at £33,350. The same figures guide pricing decisions, product launches and the case for cutting a cost.

Margin of safety measures the cushion between where you expect to be and where you would start losing money. In pounds it is expected sales less break-even sales, and as a percentage it is that gap divided by expected sales. With expected sales of £50,000 against a break-even of £33,350, the margin is £16,650, or 33%. A stable business usually runs at 25 to 50%. Below 15% a modest dip in sales pushes you into loss, while above 50% you are either carrying excess capacity or charging less than the market would bear.

Three levers move the break-even point. Cutting fixed costs, by renegotiating rent, moving to flexible workspace such as WeWork, outsourcing non-core functions or replacing perpetual licences with software as a service, helps immediately. Cutting variable costs through bulk discounts, wider sourcing or automation scales with volume. Raising the price is the strongest of the three, since even a 5% increase typically reduces break-even by roughly 15%, although the market has a vote. Shifting the product mix towards higher-margin lines does much the same. Trim a £20,000 fixed cost base by a tenth and break-even falls from 667 units to 600.

The theory is easier than the reality. An average UK small business takes 2 to 3 years to reach sustainable break-even according to Companies House data, and 60% fail within the first 3 years, mostly through cash flow rather than the break-even point itself, having run out of money before the sales arrived. That makes a 6-month cash buffer more valuable than a precise contribution margin. SEIS and EIS investment exists to trade on that risk profile, and R&D tax credits, worth 27% in effective Corporation Tax relief since 2023, lower the effective break-even for businesses doing qualifying development work.