How it works
One product or service with constant selling price and unit cost. Percentage fees apply to the full selling price; the additional fee applies per unit, not per order. Gross margin and markup exclude variable fees; contribution includes both fee types. Fixed costs and sales quantity must cover the same time period. Taxes, inventory timing, financing and volume discounts are excluded. Break-even rounds up to whole units. With zero or negative contribution, additional sales cannot cover positive fixed costs. Margin is undefined at a zero price; markup is undefined at zero unit cost.
The formulaGross margin = (price − cost) ÷ price. Markup = (price − cost) ÷ cost. Contribution = price − cost − percentage fee − per-unit fee. Profit = units × contribution − fixed costs. Break-even units = round up(fixed costs ÷ positive contribution).
Good to know
Are these personalized financial recommendations?
No. These are arithmetic planning tools with editable hypothetical assumptions. Actual account terms, taxes, fees, cash flows and lender statements can differ.
Where do my numbers go?
Calculation inputs stay in this page. The finance tools do not place them in links, make calculation requests or save them automatically. CSV and print exports are created only when you choose them. Existing site delivery and performance services still operate; see Privacy.
Which currency and rounding do you use?
Choose a display currency and enter every amount in that same currency. No exchange conversion is performed. These tools use two-decimal money displays. Loan and debt schedules round monthly interest and balances to cents; savings models keep internal precision. Values are bounded to keep calculations reliable.