The formula
How to calculate break-even point
The break-even point is the number of units at which a business stops losing money and starts making it. Below it, every sale reduces the loss; above it, every sale is profit.
The logic is simple: each unit contributes its price minus its variable cost towards fixed costs. Divide the fixed costs by that contribution and you have the number of units needed to clear them.
Here is what each field means:
- Fixed costs
- Selling price per unit
- Variable cost per unit
The result updates on every keystroke. The URL updates too, which makes the filled-in version easy to bookmark or send to someone else.
Some of the fields above will accept figures that seem unusual for your own situation, and that is deliberate: the formula behind break-even point works the same way regardless of scale, so the calculator does not stop you testing a hypothetical scenario a long way from your actual numbers — often the fastest way to see which input the result is most sensitive to.
Why break-even point matters
Most people who look up a break-even point calculation already have a specific number in mind — a quote, an offer, a target — and want to check it rather than learn the theory behind it. This page is built for that: enter your own figures, see the result immediately, and change any field to see how the answer moves without redoing the arithmetic from scratch each time.
Beyond a one-off check, the same calculation is worth revisiting whenever the underlying numbers change — a new interest rate, a change in income, a different term. Because the figures live in the page's own web address, coming back to update just one field and compare the new result against the old one takes seconds rather than starting again from a blank page.
It is also worth being clear about what a single figure like this can and cannot settle on its own. It answers the specific question the formula was built to answer, and nothing more — a favourable break-even point result does not automatically mean a decision is a good one overall, since plenty of other factors that a formula cannot capture, from personal circumstances to how comfortable a commitment feels, usually matter just as much as the arithmetic. Use the number as one solid input among several rather than the whole of the decision.
Where the same calculation needs to be run for several different scenarios side by side — three loan offers, two savings plans — the fastest approach is usually to open the calculator in a second browser tab for each one, so that the results can be compared directly rather than overwriting each other in a single set of fields.
Worked example
Here is the calculation with the starting values:
- Fixed costs: 150,000
- Selling price per unit: 45
- Variable cost per unit: 27
That gives:
- Break-even units: 8,333.33 units
- Units per month: 694.44 units
- Break-even revenue: 375,000
These figures are only the calculator's own starting values, included so the working is visible rather than hidden inside the tool above. Replace them with your own numbers and the same arithmetic applies — nothing about the method changes, only the inputs feeding it.
Reading the result
The monthly figure is the one to test against reality. A break-even of 8,333 units a year is 694 a month — either obviously achievable or obviously not, in a way the annual figure conceals.
Where this goes wrong. Treating break-even as the goal. It is the survival threshold, not the target. A plan that reaches break-even in month eleven of twelve leaves nothing for reinvestment, tax or the founders.
A useful check on any unfamiliar result is to compare it against a rough mental estimate first — round the inputs to convenient numbers and see whether the calculator's answer lands in roughly the same territory. A wildly different figure usually means one of the fields was entered in the wrong unit, most often a percentage typed as a whole number where a decimal was expected, or the reverse.
Raise the price, cut the variable cost, or reduce fixed costs. Price is usually the most powerful: a 10% rise with unchanged costs can cut break-even volume by a quarter.
Use the contribution margin ratio on total revenue instead of per-unit figures. That gives break-even in revenue terms, which works across a mixed product range.
The answer it gives you is break-even units. With 150,000 fixed costs, 45 selling price per unit and 27 variable cost per unit, that comes to 8,333.33 units. Change any field and the figure moves with it.
Whenever one of the underlying figures changes — a new interest rate, a different balance, an updated term — since the result only reflects what is currently in the fields. There is no need to keep a separate record of past results; the web address for a filled-in version already carries the figures used to produce it.
Not unless a tax rate or a fee is explicitly one of the inputs above. Where it is not, the figure shown is a gross calculation, and any tax due depends on your personal circumstances and current tax rules, which are worth checking separately.
The arithmetic itself is exact — the calculator applies the formula shown above precisely, with no rounding until the final figure is displayed. The uncertainty, where it exists, is entirely in the inputs: an estimated rate or an approximate balance carries that same approximation through to the result.