Retail operations
Break-even sales per day.
Enter monthly fixed costs, gross margin and days open. See the sales per day and transactions per day that break even, and what a profit target adds.
Break-even sales = fixed costs / (gross margin % - other variable cost %). $18,500 of fixed costs at a 42% contribution needs $44,047.62 a month, $1,694.14 a day over 26 days.
Your numbers
Result
Worked example
A shop has $18,500 of monthly fixed costs, a 45% gross margin and 3% of sales going to card fees, leaving a 42% contribution. Break-even sales are 18,500 / 0.42 = $44,047.62 a month. Open 26 days, that is $1,694.14 a day, or 44.6 transactions at $38. To also earn $2,000 a month, sales must reach $48,809.52, which is $1,877.29 a day and 49.4 transactions. If the shop averages $2,000 a day today, its break-even is 15.29% below today's sales, a 15.29% margin of safety.
How it works
Contribution % = gross margin % - other variable costs %. Every dollar of sales contributes that share toward fixed costs. Break-even sales = fixed costs / contribution %, and the profit-target version adds the target to the fixed costs first.
Daily sales = monthly sales / days open, and transactions per day divides that by your average transaction. Margin of safety = (current daily sales - break-even daily sales) / current daily sales. It is blank if you leave the current field empty.
Keep fixed costs to costs that do not move with sales in the month, and put anything that does move, such as payment fees or sales commissions, in the variable share. Seasonal stores should run the tool for a slow month and a busy month rather than average the year.
Sources and basis (checked 2026-10-08): Arithmetic on your inputs only. Break-even is fixed costs divided by contribution margin, a standard cost-volume-profit identity applied to the figures you enter.
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FAQ
How do I calculate break-even sales per day?
Divide monthly fixed costs by your contribution margin to get break-even sales for the month, then divide by the days you are open.
What counts as a fixed cost for a store?
Costs that stay about the same whatever you sell in a month, such as rent, salaried or scheduled payroll, insurance and software. Costs that rise with sales belong in the variable share.
Why add a profit target?
Break-even only covers costs. Adding the monthly profit you need, including an owner draw if you want one, shows the sales level that actually meets your goal.