Break-Even Calculator
Find the number of units you need to sell to cover fixed costs — and how many more to hit a target profit.
With £10,000.00 in fixed costs and a contribution margin of £20.00 per unit (40.0% of price), you need to sell 500 units — that's £25,000.00 in revenue.
Results update as you type. Match the period of fixed costs to the period you want to break even over (e.g. monthly fixed → monthly break-even units).
Formula
Break-even units come from a single division:
units = fixed_costs / (price − variable_cost).
The denominator is the contribution margin per unit. Add a target profit to budget upward:
units = (fixed + target_profit) / (price − variable_cost).
The result is rounded up because partial units don't sell — selling 142 of 142.86 leaves you
short of break-even.
Related calculators
Frequently asked questions
What's the difference between fixed and variable costs?▾
Fixed costs don't change with how much you sell — rent, salaries, software subscriptions, business rates, insurance. Variable costs scale with sales — raw materials, packaging, payment processing fees, sales commission, per-unit shipping. The split isn't always clean (some costs are 'semi-variable'), but for break-even maths the rule is: if it costs the same whether you sell 100 or 1000 units, it's fixed; if it scales, it's variable.
What does 'contribution margin' mean?▾
It's the gap between your selling price and the variable cost of that unit — what each sale 'contributes' to covering fixed costs and (eventually) profit. If you sell at £50 and the variable cost is £30, every unit contributes £20 toward fixed costs. Once fixed costs are covered, every additional unit's contribution is profit. Contribution margin ratio expresses the same thing as a percentage of price (£20 / £50 = 40%).
Why does the calculator round up?▾
Because you can't sell 142.857 units. If the maths says you need 142.857 to break even, selling 142 leaves you slightly below — 143 is the actual minimum to clear costs. The 'exact' figure is shown beneath the headline for completeness, but the rounded number is the actionable one.
How do I use this for a service business with no 'units'?▾
Treat your billable hour, day, or project as the unit. For a £100/hour consultant: price per unit = £100; variable cost per unit = direct costs of delivering an hour (subcontractor rates, project-specific software, travel for that hour). Fixed costs are your monthly overhead. The break-even unit count is then how many billable hours/days/projects you need a month.
What's the difference between break-even and target-profit modelling?▾
Break-even (target profit = 0) tells you when you stop losing money. Target-profit modelling (target > 0) tells you when you start hitting a profit goal. The maths is the same — you're just adding the desired profit to the fixed-cost figure: units = (fixed + target profit) / contribution margin. Use it for budgeting: 'we need £30k of net profit, so we need to sell X units'.
Should I use monthly or annual figures?▾
Either, but be consistent. If fixed costs are monthly (£10k/month rent + salaries), the break-even is units per month. If you put in annual fixed costs (£120k/year), the break-even is units per year. Mixing periods (annual fixed costs with monthly target profit) gives nonsense numbers.