How to Calculate a Business Break-even Point

Every business has a point where the money coming in finally covers the money going out. Below it, sales only make the loss smaller; above it, each additional sale adds profit. Knowing where that point sits turns a vague sense of needing more work into a number you can plan around.

This guide explains the contribution method, the difference between fixed and variable costs, and how to use a break-even figure before you commit to a cost rather than after.

Fixed costs, variable costs and contribution

Fixed costs stay roughly the same whether you sell one unit or a hundred: rent, insurance, software subscriptions, salaried staff, loan repayments. They are incurred by being open.

Variable costs move with volume: materials, stock, packaging, delivery, payment processing, subcontractor hours. They are incurred by selling.

Some costs sit awkwardly in between. A utility bill has a standing charge and a usage element; a member of staff paid hourly is fixed in practice if their hours cannot be cut. The classification does not have to be perfect, but it has to be consistent, because the entire calculation depends on it.

Contribution per unit

The contribution is what each sale leaves behind after its own variable costs, ready to pay the fixed costs.

Contribution per unit = selling price - variable cost per unit.

The word is deliberate. A sale does not contribute its price to the business; it contributes the difference between the price and what that sale cost to fulfil. A 45 sale with 27 of variable cost contributes 18.

The break-even formula

Break-even in units = fixed costs / contribution per unit.

Break-even in revenue = break-even units × selling price.

The formula assumes the price and the variable cost stay the same at every volume. That is true enough over a modest range and increasingly wrong beyond it, because volume discounts, overtime, and bulk material savings all move the inputs.

Worked example: 334 units

A business has fixed costs of 6,000 a month. It sells a product at 45, and the variable cost of each unit is 27.

Contribution per unit: 45 - 27 = 18.

Break-even units: 6,000 / 18 = 333.33.

You cannot sell a third of a unit, so the practical break-even is 334 units. At 333 units the business is 6 short of covering its fixed costs; at 334 it is 12 into profit.

Break-even revenue: 334 × 45 = 15,030. Using the exact figure, 333.33 × 45 = 15,000, and the difference is the rounding.

That 334th unit is worth more than the first. Every unit sold before break-even contributes 18 towards costs that would be incurred anyway; every unit after it contributes 18 straight to profit. This is why volume beyond break-even changes a business's finances so quickly.

Break-even in time and in capacity

Units are useful for planning, but only if you know whether you can sell them.

If the business sells 100 units a month, break-even arrives after 3.34 months of trading — early in the fourth month. If it can only produce 250 units a month, it never breaks even, and either the price or the fixed cost base has to change.

Comparing break-even units with realistic capacity is the step most likely to produce an uncomfortable answer, and the most valuable one. A break-even of 334 units against a capacity of 300 is not a sales target; it is a warning.

Using break-even before you commit

The calculation is most useful before money is spent. Three questions it answers:

• Should I take on this fixed cost? A 900 a month subscription needs 50 extra units at an 18 contribution before it pays for itself.
• Is this discount safe? A 5 reduction in price cuts contribution to 13 and raises break-even to 462 units. That is the real cost of the discount.
• Which offer is better? A product with a higher contribution but slower sales may break even later than a cheaper one that turns over quickly.

Common mistakes

• Putting variable costs in the fixed bucket. A cost that rises with every sale, treated as fixed, understates break-even and overstates safety.
• Forgetting the owner's pay. If the business must support you, that figure is a fixed cost, not a profit.
• Using a discounted price in the calculation and a full price in the plan. Break-even at the price you actually achieve is the only figure that helps.
• Ignoring stepped costs. Rent and staff arrive in chunks; a break-even that assumes smooth capacity can be wrong by a whole hire.
• Treating break-even as a target. It is the point where profit is zero. Aiming for it is aiming to make nothing.

Next step

Run your own figures through the break-even calculator to get units and revenue together, then check what your current sales volume implies with the profit calculator. If the break-even number is higher than your capacity, the answer is usually a price change or a cut in fixed costs — and it is much cheaper to find that out now.