Fixed and variable costs
Fixed costs stay the same whatever you sell in a month: rent, insurance, salaried pay, software, loan payments. Variable costs rise with each sale: materials, shipping, card fees, commissions. Some costs are mixed, such as utilities, and need to be split by judgment.
Your profit and loss from the books is the starting point. Go line by line and decide which type each is.
Contribution margin
Each sale leaves something after its variable cost. That amount is the contribution toward fixed costs. As a percentage of sales, it is the contribution margin. If variable costs are thirty-five percent of sales, the contribution margin is sixty-five percent.
It is similar to gross margin, but it counts all variable costs, not just the ones labeled as cost of goods.
The formula
Break-even sales equal fixed costs divided by the contribution margin percentage. If fixed costs are twenty thousand a month and the contribution margin is sixty-five percent, break-even sales are about thirty thousand eight hundred. Below that you lose money, above it you earn it.
For a product business, you can also express it in units: fixed costs divided by contribution per unit.
Include your own pay and debt
A break-even that ignores owner pay and loan principal is misleading. Principal is not an expense, but it must be paid from cash. Add it to the fixed amount if you want a cash break-even, and add a reasonable owner salary. That version tells you the sales you need to actually survive.
Compare both versions: the accounting figure and the cash figure.
Using the number
Break-even helps with hiring, price changes and new leases. If a new hire adds a fixed cost, divide it by your contribution margin to see the extra sales required. If a price rise increases the contribution margin, the break-even point falls.
Test what happens if sales dip. How far above break-even are you now? That cushion is your margin of safety, and it shows how much risk you carry.
Keep it current
Costs and margins shift. Recalculate each quarter, or when you make a major change. Seasonal businesses should use annual figures and monthly versions.
Treat the result as an estimate. Real life has discounts, waste and timing. Still, an approximate break-even is far better than none.
A small studio has fixed costs that include rent, insurance, software and the owner's modest pay. Its variable costs are materials and card fees. The break-even calculation shows it needs a certain number of clients per month. The owner then considers hiring an assistant. Dividing the assistant's cost by the contribution per client shows exactly how many extra clients are needed to pay for the hire. The decision becomes a question of marketing capacity, not a guess.
Common questions
Is break-even the same as profit?
No. At break-even, profit is zero.
Do I include taxes?
Income taxes are usually separate. Include payroll and sales-based costs. Ask your CPA about tax planning.
How often should I recalculate?
Quarterly, and whenever a major cost or price changes.
This guide is general information, not tax, legal or accounting advice. Rules, fees and due dates change; check with the IRS, the NJ Division of Taxation or a licensed professional for your situation.