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· 4 min read
How to Find Your Break-Even Volume
Heshan Fernando
Co-founder & COO
You sell at 4,500. It costs 2,700 to make. Fixed costs are 540,000 a month. How many do you need to sell before the business makes money?
The answer isn’t 540,000 divided by 4,500, and the difference between those two calculations is the most useful concept in small-business finance.
Contribution, not revenue
Each sale brings in 4,500 and costs 2,700 in materials and direct labour. What’s left — 1,800 — is the contribution: the amount that unit contributes toward covering fixed costs, and after those are covered, toward profit.
break-even units = fixed costs ÷ contribution per unit
540,000 ÷ 1,800 = 300 units.
Unit 300 covers the last of the fixed costs. Unit 301 contributes 1,800 straight to profit, because the fixed costs are already paid. That’s why contribution is the number that matters for any decision about one more sale.
Dividing fixed costs by the selling price instead gives 120 units, which assumes each sale contributes its entire revenue and ignores that making the thing costs money.
What counts as variable
The distinction is whether the cost changes with volume, and it’s less obvious than it looks.
Genuinely variable: materials, packaging, shipping per order, payment processing fees, direct labour where it actually scales with output.
Fixed despite feeling variable: rent, salaried staff, software subscriptions, insurance, equipment leases. These don’t change when you sell one more unit.
Stepped: costs that are fixed within a range and jump at a threshold — a second delivery van, another shift, more warehouse space. These behave as fixed until volume crosses the step, at which point break-even recalculates.
Misclassifying salaried production staff as variable is the most common error, and it makes contribution look better than it is.
| Cost | Type | Note |
|---|---|---|
| Materials | Variable | Scales directly |
| Payment fees | Variable | Percentage of each sale |
| Rent | Fixed | Same at any volume |
| Salaried staff | Fixed | Even in production roles |
| Extra delivery van | Stepped | Fixed until you need it |
Where the number changes decisions
Pricing. A price increase raises contribution per unit and lowers break-even. A 10% price rise on our example takes contribution from 1,800 to 2,250 and break-even from 300 units to 240 — a 20% reduction in the volume needed, from a 10% price change.
Discounting. The reverse, and it’s brutal. A 10% discount cuts contribution to 1,350 and pushes break-even to 400 units. You need a third more volume to stand still.
Marginal orders. Spare capacity and an order above variable cost but below full cost still contributes toward fixed costs you’re paying regardless. That’s sound reasoning for genuinely spare capacity and a dangerous habit as a general policy.
Common mistakes to avoid
- Dividing fixed costs by price rather than by contribution.
- Classifying salaried production staff as a variable cost.
- Ignoring stepped costs, so break-even looks stable across a range where it isn’t.
- Using contribution reasoning to justify routine discounting, which erodes the margin the whole model depends on.
- Calculating once and never revisiting when input costs move.
How to do it with Contribution Margin Calculator
The Contribution Margin Calculator reports the margin and the break-even volume together.
- Enter the selling price and the genuinely variable cost per unit.
- Add fixed costs for the period.
- Read break-even volume alongside contribution per unit.
- Test a price change and a discount — the asymmetry is worth seeing.
Other business calculators are in the tools directory.
Frequently asked questions
What counts as a variable cost?
Costs that change with each unit — materials, direct labour where it genuinely scales, transaction fees, shipping. Rent and salaried staff are fixed even though they feel variable when you’re paying them.
Why is contribution margin more useful than gross margin?
Because it isolates the decision-relevant number. When deciding whether one more sale is worth it, fixed costs are already committed — contribution tells you what that sale actually adds.
Should I ever sell below full cost?
Above variable cost and below fully-absorbed cost, an extra sale still contributes to fixed costs you’re paying anyway. Sound for genuine spare capacity, dangerous as a general pricing policy.
Final thought
Work out what a 10% discount does to your break-even volume. Most people discount without doing that calculation, and most stop once they have.