The number that tells you when the lights stay on

Ask most owners how much they need to sell each month just to not lose money, and you get a shrug or a guess. That number has a name — the break-even point — and it's one of the most clarifying figures in all of small-business finance. Below it, every month bleeds. Above it, every additional dollar starts building profit. This guide walks through the handful of inputs you need and the simple arithmetic that turns them into a sales target you can actually steer by.

This is general education, not financial advice — your specific situation may have wrinkles worth discussing with an accountant.

Step 1: separate fixed costs from variable costs

Break-even rests on one distinction, so get it right first:

  • Fixed costs stay roughly the same no matter how much you sell — rent, salaries, insurance, software subscriptions, loan payments. You pay them whether you make one sale or a thousand.
  • Variable costs rise and fall with sales — materials, the direct labor or subcontractors tied to a job, payment-processing fees, shipping. These are essentially your cost of goods sold.

Consistent expense categorization is what makes this split reliable. If a cost lands in a different bucket every month, your break-even number wobbles for no real reason.

Step 2: find your contribution margin

Contribution margin is what's left from each sales dollar after variable costs — the part that "contributes" to covering fixed costs and then profit.

  • As a percentage: (Revenue − Variable Costs) ÷ Revenue. If a $100 sale carries $40 of variable cost, your contribution margin is 60%. This is the same idea as gross margin viewed through the lens of fixed-cost coverage.
  • Per unit: if you sell one product, it's simply price minus variable cost per unit. A $50 product that costs $20 to deliver contributes $30 per sale.

Contribution margin is the engine of the whole calculation — it's the rate at which each sale chips away at your fixed costs.

Step 3: do the break-even math

The formula is short:

Break-even revenue = Fixed Costs ÷ Contribution Margin %

Say your fixed costs are $30,000 a month and your contribution margin is 60%. You must sell:

$30,000 ÷ 0.60 = $50,000 in revenue every month just to break even.

Every dollar above $50,000 converts to profit at 60 cents on the dollar. Every dollar below means you're dipping into reserves. If you'd rather think in units, divide fixed costs by the per-unit contribution margin instead: $30,000 ÷ $30 = 1,000 units to break even.

Adding a profit target

Break-even is the floor, not the goal. To find the sales needed to hit a profit target, just add the target to fixed costs before dividing:

Required revenue = (Fixed Costs + Profit Goal) ÷ Contribution Margin %

Want $12,000 of monthly profit on top of that $30,000 of fixed costs at a 60% margin? You need ($30,000 + $12,000) ÷ 0.60 = $70,000 in sales. Suddenly an abstract wish ("I'd like to clear another twelve grand") becomes a concrete, trackable sales number.

What break-even is good for

  • Pricing decisions. If a price cut drops your contribution margin, your break-even point rises — sometimes more than the extra volume can cover. Run the math before you discount.
  • Hiring and overhead. A new salary is a new fixed cost. Adding $5,000/month in payroll at a 60% margin raises your break-even by $8,333 in sales. Knowing that turns a gut call into an informed one.
  • Survival planning. In a slow stretch, knowing your break-even tells you exactly how lean you'd have to get — or how much sales would have to recover — to stop the bleeding.

A caveat worth keeping in mind

Break-even is a model, and models simplify. The fixed-versus-variable line is fuzzier than it looks — some costs are "stepped" (you don't need a second delivery van until volume crosses a threshold), and a single blended contribution margin hides differences between your products. Treat break-even as a sharp estimate that guides decisions, not gospel to the penny.

Still, few numbers reward five minutes of arithmetic this richly. Hosting Books surfaces the fixed-cost, variable-cost, and margin figures straight from your reconciled ledger, so your break-even point isn't a once-a-year spreadsheet — it's a number you can check against reality every month right after your month-end close.

This article is general information, not financial advice. Your cost structure and the right way to model it depend on your facts — confirm with a qualified accountant.