What break-even analysis actually asks
One question: how much do I have to sell before the money coming in matches the money going out? That's a lower bar than rich or even good. It's the point where the business stops losing, the floor of the whole plan, and everything above it gets measured from there.
The question has a clean answer because costs split into two kinds that behave completely differently. Fixed costs happen whether you sell nothing or everything: the lease, the salaries, the accountant, the software subscriptions, the insurance. Variable costs exist only because a sale happened: materials, packaging, the shipping label, the payment fee. Sell one more unit and the fixed side stays put while the variable side goes up by exactly one unit's worth.
That difference is why a break-even point exists at all. Revenue grows with volume in a straight line from zero. Total cost grows with volume too, but it starts high, at the fixed cost, and climbs more slowly as long as each unit brings in more than it costs. Two straight lines with different slopes cross exactly once. That crossing is the break-even point.
Contribution margin is the number that moves
Price minus the variable cost of one unit is the contribution margin, and the whole subject turns on it. Sell a $50 item that costs you $20 to make and deliver, and each sale puts $30 toward the fixed cost. Until the fixed cost is paid off, that $30 isn't profit. Once it is, every further $30 is profit in full.
So the break-even point is fixed cost divided by contribution margin. $12,000 of fixed cost at a $30 margin needs 400 units. Multiply by the price and you get break-even revenue: $20,000. Same fact, different units, which is why the revenue figure in this calculator is always exactly the unit figure times the price.
Thinking in contribution margin instead of profit changes what you decide. Profit is something you see at the end of the month. Contribution margin is a lever you can pull today. Raise the price by $5 and the margin goes from $30 to $35, and break-even drops from 400 units to 343. That's a 14% cut in the volume you need from a 10% price change. Cut the variable cost by $5 and you get exactly the same effect. Trying to fix a loss by selling more, without touching either side of that gap, is just running faster in the same direction.
When there is no break-even point at all
If the price is at or below the variable cost, the contribution margin is zero or negative and there is no break-even point. This is the most important thing a break-even calculator can tell you, far more than a tidy edge case, and most of them get it wrong.
Divide fixed cost by a zero margin and the math returns infinity. Divide by a negative one and it returns a negative quantity: with $12,000 of fixed cost and a price $2 below variable cost, the formula gives −6,000 units. A tool that prints that number is showing a business owner something that looks like a target. In reality, at a negative margin every sale digs the hole deeper, and the better the marketing campaign works, the faster the money disappears.
This calculator refuses to give a figure in that case and shows what would have to change instead: the price the unit would need to reach, or the variable cost it would have to fall to. Selling below variable cost can be a deliberate short-term move (a loss leader, an introductory offer, clearing dead stock). Make it a decision with your eyes open, not a number quietly divided.
Percentage costs are not per-unit costs
Some variable costs are a fixed amount per unit: the fabric, the box, the courier label. Others are a percentage of the selling price: card processing, marketplace commission, sales commission, revenue-based taxes and percentage rent in a shopping center. They look alike in a spreadsheet and behave completely differently the moment the price changes.
A 2.9% payment fee on a $100 sale is $2.90. On a $200 sale it's $5.80. Enter it as "$2.90 per unit" while selling at $100 and your break-even goes silently wrong the moment you raise the price, in the dangerous direction: it tells you the margin is fatter than it is. That's why the percentage field in this tool sits apart from the money-per-unit field and gets applied to the price instead of added to the unit cost.
It's also why the example this page opens with shows 421 units instead of the 400 a $30 margin would suggest. The default includes a 2.9% card fee, which is $1.45 on a $50 sale. The margin drops to $28.55 and the volume you need climbs by 21 units. A fee most people round to nothing is worth five percent of the target.
Percentages stack, too. A seller taking cards at 2.9%, paying a 5% sales commission and handing 15% to a marketplace loses 22.9% of every sale before a single physical cost is counted. As a contribution margin, that means the margin ratio can never go above 77.1% however cheap the product is to make, and that ceiling often decides whether a channel is worth selling through at all.
Break-even with a profit target
Break-even is rarely the real goal. The real question is usually "how much do I have to sell to make $6,000 this month?" The answer uses the same division with the target added to the fixed cost: (fixed cost + target profit) ÷ contribution margin.
A profit target acts exactly like extra fixed cost: money you have to cover before you're satisfied, on top of what you need to be solvent. It moves the required volume by target ÷ margin units. Get this into your head: at a $30 margin, every $3,000 of profit you want costs another 100 units of sales, however big the fixed cost already is. If that extra volume isn't realistic in your market, the margin has to change. The target won't reach itself.
Flip the same formula to answer the reverse question. Given a volume you're confident you can sell, profit is volume × margin − fixed cost. If you're writing a business plan, run it both ways: what the plan needs, and what the market will plausibly give you.
Accounting, cash and economic break-even
There are three break-even points, and each answers a different question. Mix them up and you can shut down a product that was still paying its way, or keep one that was quietly destroying value.
| Type | Fixed cost used | Question it answers |
|---|---|---|
| Accounting | All fixed costs | When does the income statement show zero? |
| Cash | Fixed costs minus depreciation | When does the bank balance stop falling? |
| Economic | Fixed costs plus a required return on capital | When does the business beat leaving the money elsewhere? |
Depreciation is a real cost of a machine wearing out, but no cash leaves the account for it this month. The money left when you bought the machine. Take it out and you get the cash break-even, which sits below the accounting one and is the number that counts when the question is whether you'll survive the next quarter. Below the cash break-even you're burning money you actually have. Between the two, you're shrinking on paper while the account holds.
The economic break-even goes the other way. Capital tied up in the business could be earning a return somewhere else, and that opportunity cost is real even though no invoice ever arrives for it. Add the return you require to the fixed cost and break-even rises. A business sitting between the accounting and economic points is profitable and still the wrong place for the money.
Margin of safety and operating leverage
Once you know the break-even point, the distance between it and what you actually expect to sell is the margin of safety, in units or as a percentage of expected sales. Expect 500 units against a break-even of 400 and your margin of safety is 100 units, or 20%: sales can fall by a fifth before the business stops covering its costs.
That one percentage tells you more about fragility than any profit figure. Two businesses can report the same profit while one runs at a 40% margin of safety and the other at 5%. The second is one slow month from trouble. It's also the fastest sanity check on a forecast. A plan that only works at 97% of its projected volume isn't a plan.
Operating leverage is the same idea from the other side. It measures how much profit swings for a given swing in sales, and it equals total contribution margin divided by profit. At 500 units with a $30 margin and $12,000 of fixed cost, leverage is 5: a 10% drop in sales cuts profit by 50%. High fixed costs and fat margins give you high leverage. Great when volume rises, brutal when it falls, and exactly why businesses near their break-even point feel so much more volatile than their revenue suggests.
More than one product: the weighted average margin
Most businesses sell several things at different margins, and a mixed basket has no single break-even quantity. 400 units means nothing if a unit might be a coffee or a cake. What you can find is a break-even for a given sales mix.
The standard method is a weighted average contribution margin. Weight each product's margin by its share of unit sales, divide the fixed cost by that average to get total units, then split them back across products in the same proportions. If the mix is unstable, use margin ratios and work in revenue instead: fixed cost divided by the weighted average contribution margin ratio gives you break-even revenue directly.
The catch: the answer only holds while the mix holds. Sell the same total volume with more of the low-margin item and the break-even point climbs without a single price or cost changing. That's why cafés push pastry with the coffee and why movie theaters care more about the concession stand than the ticket. Run this calculator per product, or on the average product you actually sell, and run it again when the mix shifts.
What this break-even model assumes, and where it stops
Break-even analysis is a straight-line model, so know its assumptions. It treats the price as constant at every volume and ignores the discounts that usually come with bigger orders. It treats variable cost per unit as constant too, ignoring both bulk purchasing savings and the overtime that shows up when you push capacity. It assumes fixed costs stay fixed, but they're only fixed within a range; a second shift, a bigger space or another van makes them jump in a step. And it assumes everything you produce gets sold, with no inventory piling up in between.
Inside that range, the model is still the most useful arithmetic in small business finance, because it turns vague worry into a number you can test against reality: can we plausibly sell that many? None of the figures you type here leave your browser. There is no account, no upload and nothing stored.
Frequently asked questions
What is the break-even formula?
Units to break even = fixed cost ÷ contribution margin per unit, where contribution margin is the selling price minus the variable cost of one unit. In revenue terms it's fixed cost divided by the contribution margin ratio, which is the same answer multiplied by the price. Everything else in break-even analysis (profit targets, margin of safety, operating leverage) is a variation on that one division.
What if the price is lower than the variable cost?
Then there is no break-even point, and the calculator says so instead of printing a number. With a negative contribution margin, every extra sale makes the loss bigger, so no amount of volume saves the business. The arithmetic would spit out a negative quantity, and that isn't a smaller target. It means the formula no longer applies. You have two fixes: raise the price above the variable cost, or cut the variable cost below the price.
How do card fees and sales commissions fit in?
They're variable costs that scale with the price instead of the unit, so put them in the percentage field, not the per-unit one. A 2.9% processing fee costs 29 cents on a $10 product and $2.90 on a $100 one. Entering it as a flat amount per unit is only right at the one price where you worked it out, and it drifts further from the truth every time you change the price.
How many units do I need for a specific profit?
Add the profit you want to the fixed cost and divide by the contribution margin: (fixed cost + target profit) ÷ contribution margin. A profit target works exactly like extra fixed cost, so it moves the break-even point by target profit ÷ contribution margin units. On a $30 margin, every $3,000 of profit you want costs another 100 units of sales.
What is a good margin of safety?
That depends on how volatile your sales are, but the number is easy to read: it's the percentage your expected sales can drop before you stop covering costs. Below about 20%, one slow month puts you under water. Under 10%, the plan only works if nothing goes wrong. A high margin of safety is what lets a business get through a bad quarter without borrowing.
Does the break-even point include tax?
It includes any tax that behaves like a cost of doing business. Taxes charged as a percentage of revenue go in the percentage field with card fees and commissions, because they rise with every sale. Corporate income tax on profit stays out of the calculation entirely: at break-even, profit is zero, so tax on profit is zero too. Adding it would move a point that by definition it doesn't touch.