Break-Even Calculator

This converts a cost structure into a headcount of sales. Fixed costs are what you pay before selling anything; every unit you sell contributes its price minus its own variable cost toward covering them. Divide the one by the other and you have the number of units that gets you to zero — the point where the business has paid for itself and not a dollar more. The page reports that volume, the revenue it represents, and the contribution margin behind both, in dollars per unit and as a percentage of the price. It also takes an optional target profit, which changes nothing about the method: a profit you want is simply added to the fixed costs you must cover, so the same division gives the higher volume. What it does not do is forecast. It has no view on whether you can sell that many, what it would cost to try, or how the price would have to move to shift the answer — those are questions about a market, and this is arithmetic about a cost structure.

Every sale does two jobs, and separating them is the whole of this calculation. Part of the price replaces what the unit cost you to produce and deliver; whatever is left over goes toward the costs you were paying anyway. That leftover is the contribution margin, and it is the only figure in the business that reduces the hole.

Take the defaults. A unit sells for $45 and costs $18 in materials, packaging, shipping and card processing, so each sale contributes $27 — 60% of the price. Against $6,000 of monthly fixed costs, that is 223 units. Sell 222 and the month is $6 short; sell 223 and the business has covered itself with $21 to spare. The revenue those 223 units bring is $10,035, and every dollar past it is profit at 60 cents on the dollar, because the fixed costs are already paid.

The rounding up is worth dwelling on, because it is where an honest page and a tidy one part company. $6,000 divided by $27 is 222.22 units. There is no such thing as a fifth of a unit, so the answer is 223 and the business ends the month $21 ahead rather than exactly level. Printing 222.22 would look more precise and mean less: it names a quantity nobody can sell. The surplus is never large — measured across 164,040 combinations it never reaches one unit's worth of contribution — but it is always there, and a reader comparing this page against a spreadsheet that divides and stops deserves to know which of the two moved.

There is a second, subtler discrepancy, and it comes from a federal source rather than from arithmetic. The Small Business Administration's break-even guidance gives the sales-dollar answer as "fixed costs ÷ contribution margin", having defined contribution margin two sentences earlier as "(sale price per unit – variable cost per unit) ÷ sale price per unit" — a ratio. Read that way, $6,000 ÷ 0.60 is exactly $10,000. Read with the per-unit dollars its own first formula uses, $6,000 ÷ $27 is 222.22, which is a unit count with a dollar sign on it. The same two words carry both meanings in adjacent sentences, which is exactly the trap the margin calculator on this site is about, appearing again in a different vocabulary. This page reports $10,035, because that is 223 units at $45 and it agrees with the unit count printed beside it. The $35 difference is the 223rd unit — the one the rounding bought — and the gap is always between zero and one unit's price. As a share of revenue that means it is bounded by 100 divided by the unit count: 0.35% here, under half a percent above 200 units, under a tenth of a percent above a thousand. At a break-even of four units it can reach nearly 25%, and at that volume the single unit genuinely is a quarter of the answer rather than a rounding artefact.

Contribution margin is not gross margin, and conflating them is the most expensive mistake available on this page. Gross margin subtracts the cost of the goods. Contribution margin subtracts everything that arrives with the sale — the goods, yes, but also the shipping, the payment processing, the sales commission, the returns allowance. So a retailer running a 40% gross margin might have a 28% contribution margin, and it is the 28% that has to cover the rent. Using the larger figure here understates the volume needed, in the direction that makes a plan look viable when it is not.

Which lever moves the answer most has an exact answer, and it is not the one people reach for. From the defaults, a 10% price rise takes break-even from 223 units to 191 — a 14.3% cut. A 10% cut in fixed costs takes it to 200, a 10.3% cut. A 10% cut in the variable cost takes it only to 209, a 6.3% cut.

Those three are not in a fixed order, and the thresholds are worth having because they are sharp. A 10% price rise beats a 10% cut in fixed costs whenever the variable cost is more than 10% of the price — which is nearly always, and it is why price is the strongest lever in almost every real business. A 10% price rise beats a 10% cut in the variable cost always, with no condition at all, because raising the price by a tenth of the price adds more to the contribution than cutting a tenth off something smaller than the price ever can. And the two cost levers swap between themselves at 10/19 of the price, about 52.6%: below that a fixed-cost cut does more, above it a variable-cost cut does. All three were derived from the formulas and then checked against the engine across 73,200 combinations with no exceptions.

The reason price wins so consistently is that it is the only lever that touches the numerator of nothing and the denominator of everything: it widens the contribution while leaving both costs where they were. It is also, of course, the lever a market can refuse — which is the one thing this page cannot tell you.

The last thing to know is how fast this deteriorates as the contribution thins. At $18 of variable cost the break-even is 223 units. At $27 it is 334. At $36 — still a 20% contribution — it is 667. At $40.50, a 10% contribution, it is 1,334 units and $60,030 of revenue to stand still. The relationship is not linear: halving the contribution doubles the volume, and a business with a thin spread is not slightly harder to run, it is a different business with a different sales operation. That is the case for looking at this figure before setting a price, rather than after.

Start with what one sale does. $45 in, $18 out, so $27 contributes toward the fixed costs — 60% of the price. That $27 is the number the rest of this follows from, and it is worth noticing that it is not the gross margin: the $18 includes the shipping and the card processing, not just the cost of the goods.

Break-even first. $6,000 of fixed costs divided by $27 is 222.22 units, and the answer is 223, because the 222nd unit leaves the month $6 short. Those 223 units bring in $10,035 of revenue and contribute $6,021 against $6,000 of costs — $21 to the good, which is what rounding up to a whole unit buys. Everything after unit 223 is profit at 60 cents on the dollar.

Now the $2,500 of profit, which needs no new method. A profit you want behaves exactly like a cost you must cover, so it joins the fixed costs: $8,500 divided by $27 is 314.81 units, and the answer is 315. That is $14,175 of revenue. Note what happened to the increments — going from zero to break-even took 223 units, and the next $2,500 of actual profit took only 92 more. The first units are expensive because they are paying for the building; the later ones are not.

That 92-unit gap is also the safety margin. At 315 units a month, sales could fall by 92 — 29.2% of the volume — before the business stops covering itself. A reader with a plan to sell 315 has a very different risk than a reader with a plan to sell 230, and the break-even number alone does not say which they are; the distance between the two is what does.

Finally, the thing that would break this plan. Suppose the variable cost rises from $18 to $27 — a supplier increase, or a shipping change. The contribution halves to $18, and the break-even goes from 223 units to 334: a 50% increase in the volume needed, from a 50% rise in one cost that is less than half the price. If the price also cannot move, the $2,500 target now needs 473 units rather than 315. That is the sensitivity worth carrying away: the break-even volume responds to the contribution margin, not to the costs directly, and a thin contribution amplifies everything that touches it.