To calculate your break-even point, divide your total fixed costs by the difference between your selling price and your variable cost per unit. The result tells you exactly how many units you need to sell, or how much revenue you need to earn, before your business stops losing money and starts generating profit. The math is straightforward once you know which numbers to plug in.
The Break-Even Formula
There are two versions of the formula depending on whether you want your answer in units sold or in total sales dollars.
Break-even point in units: Fixed Costs ÷ (Sales Price Per Unit − Variable Cost Per Unit)
Break-even point in sales dollars: Fixed Costs ÷ Contribution Margin Ratio
The contribution margin ratio is calculated as: (Sales Price Per Unit − Variable Cost Per Unit) ÷ Sales Price Per Unit. It represents the percentage of each dollar of revenue that actually goes toward covering your fixed costs. A contribution margin ratio of 0.40 means 40 cents of every sales dollar is left over after variable costs, and those 40 cents chip away at your fixed overhead until you hit break-even.
Sorting Your Costs: Fixed vs. Variable
Before you can run the formula, you need to separate your expenses into two buckets. Getting this right is the most important step, because putting a cost in the wrong category will throw off your entire calculation.
Fixed costs stay the same regardless of how much you produce or sell. Rent, property tax, insurance premiums, loan interest payments, salaried employee pay, and equipment depreciation are all fixed. If you sold zero units next month, you’d still owe these bills.
Variable costs rise and fall with your sales volume. Raw materials, packaging, shipping, sales commissions, hourly production labor, and utility expenses tied to output are variable. Sell twice as many units and these costs roughly double.
Some costs blur the line. Your phone bill might have a flat monthly fee (fixed) plus overage charges (variable). When that happens, split the expense into its fixed and variable portions. For a first pass, though, assigning each line item to whichever category dominates is good enough to get a useful estimate.
A Worked Example in Units
Say you run a small candle business. Your monthly fixed costs total $3,000, covering rent, insurance, and your website subscription. Each candle sells for $25, and the variable cost per candle (wax, wick, jar, label, shipping) is $10.
Break-even units = $3,000 ÷ ($25 − $10) = $3,000 ÷ $15 = 200 candles
You need to sell 200 candles per month to cover all your costs. Candle number 201 is where profit begins. Every candle beyond 200 contributes $15 straight to your bottom line.
A Worked Example in Sales Dollars
The sales-dollar version is especially useful when you sell multiple products at different price points and want a single revenue target rather than a unit count.
Using the same candle business, first calculate the contribution margin ratio: ($25 − $10) ÷ $25 = 0.60, or 60%.
Break-even sales dollars = $3,000 ÷ 0.60 = $5,000
You need $5,000 in monthly revenue to break even. That checks out: 200 candles at $25 each is exactly $5,000. Once monthly sales cross that threshold, you’re profitable.
How Service Businesses Calculate Break-Even
If you sell services instead of physical products, the formula works the same way. You just define your “unit” differently. A freelance graphic designer might treat one project as a unit. A consulting firm might use billable hours. A cleaning company might use one house cleaned.
Suppose you’re a freelance web developer. Your fixed monthly costs (software subscriptions, coworking space, professional liability insurance) total $2,400. You charge $150 per hour, and your variable cost per hour is $30 (subcontractor help, stock assets, project-specific tools).
Break-even hours = $2,400 ÷ ($150 − $30) = $2,400 ÷ $120 = 20 hours
You need to bill 20 hours per month to cover your costs. If you bill 30 hours, the extra 10 hours at $120 each produce $1,200 in profit.
When your service doesn’t break neatly into identical units, the sales-dollar approach is usually cleaner. Just estimate your overall contribution margin ratio across all the types of work you do, and divide your fixed costs by that ratio to get a revenue target.
What to Do With Your Break-Even Number
A break-even point by itself is just a number. It becomes powerful when you use it to pressure-test decisions.
Pricing decisions. If your break-even point is 500 units a month but you realistically can only sell 300, your price is too low or your costs are too high. Raising your price shrinks the gap between price and variable cost, which lowers the number of units you need. Try plugging in a higher price to see how many fewer sales you’d need.
Cost control. Lowering fixed costs drops your break-even point directly. Moving to a cheaper workspace, renegotiating insurance, or switching to a lower-cost software plan all reduce the revenue you need before turning a profit. Cutting variable costs has the same effect: finding a cheaper supplier or reducing packaging costs widens your per-unit margin.
New product launches. Before investing in a new product line, run the break-even calculation with the expected costs and price. If you’d need to sell an unrealistic volume to break even, reconsider the pricing or the investment.
Loan and lease commitments. Adding a new monthly payment increases your fixed costs. Run the formula again with the higher number to see how many additional sales you’ll need to still break even.
Measuring Your Cushion With Margin of Safety
Once you know your break-even point, you can calculate how much breathing room your business has. The margin of safety measures the gap between your actual (or expected) sales and the break-even level.
Margin of Safety = (Current Sales − Break-Even Sales) ÷ Current Sales
If your candle business currently brings in $8,000 a month and break-even is $5,000, your margin of safety is ($8,000 − $5,000) ÷ $8,000 = 0.375, or 37.5%. That means your sales could drop by 37.5% before you’d start losing money.
A high margin of safety means you can absorb a slow month or an unexpected cost increase without falling into the red. A thin margin of safety is a signal to build reserves, diversify revenue, or look for ways to lower your break-even point. There’s no universal “good” number, but knowing yours helps you gauge how vulnerable your business is to a downturn.
Limitations to Keep in Mind
Break-even analysis assumes your selling price stays constant, your variable cost per unit doesn’t change as volume increases, and your fixed costs remain flat. In practice, none of those hold perfectly. You might offer bulk discounts, get a volume discount on materials, or outgrow your current lease. Treat your break-even number as a solid estimate rather than a precise prediction, and recalculate whenever your costs or pricing change meaningfully.
The formula also doesn’t account for the time value of money. If it takes 18 months to reach break-even, the cash you spent in month one has an opportunity cost that the basic formula ignores. For a quick feasibility check, that’s fine. For a large capital investment, layering in a more detailed cash-flow analysis gives you a fuller picture.