Profit Margin Calculator

Calculate profit margin from revenue and cost

Profit margin shows the share of revenue left after the cost definition you enter. Put the selling price or net revenue in the first field and the matching cost in the second. The calculator returns profit dollars, margin as a percentage of revenue, and markup as a percentage of cost. Those three outputs answer different questions, so label the cost basis before using the result in pricing or advertising decisions.

For a campaign decision, ordinary gross margin may omit costs that rise with each order. The contribution margin versus gross margin guide explains why product cost alone may not represent the amount available to pay for advertising.

How to use the calculator correctly

1. Choose one unit. Calculate one order, one product, or a complete reporting period. Revenue and cost must cover the same unit and dates.
2. Use net revenue for operating decisions. Start with the amount retained after discounts, cancellations and refunds when those values are known.
3. Define cost. For gross margin, cost may be cost of goods sold. For pre-ad contribution margin, add variable payment, fulfillment, shipping, marketplace, support and expected return costs that belong to the sale.
4. Keep advertising outside the pre-ad cost input. If the goal is to determine how much margin is available for acquisition, adding ad spend before calculating that margin would count advertising twice.
5. Read margin and markup separately. A 40% margin does not equal a 40% markup.

Currency does not change the percentage as long as revenue and cost use the same currency. Do not divide a USD sale by a GBP cost without first converting one side. If tax or shipping revenue is included in the numerator, use the same policy across products and reporting periods.

Margin and markup use different denominators

Margin uses revenue as the base; markup uses cost. A product that costs $60 and sells for $100 produces $40 profit, 40% margin, and 66.67% markup. Confusing the two can create an underpriced offer. Adding a 40% markup to $60 gives a selling price of $84, which produces only a 28.57% margin because $24 ÷ $84 = 28.57%.

To find the selling price needed for a target margin, rearrange the formula: selling price = cost ÷ (1 − target margin). With $60 cost and a 40% target margin, $60 ÷ 0.60 = $100. The target must be written as a decimal, and a target of 100% makes the equation impossible for a product with positive cost.

Worked ecommerce example: build contribution margin

Suppose an order has a $150 list price, but a discount reduces collected revenue to $120. Matching variable costs are $42 for the product, $9 for fulfillment and packaging, $4 for payment and marketplace fees, and a $6 expected allowance for returns and customer-service handling. The relevant cost input is $42 + $9 + $4 + $6 = $61.

• Net revenue: $120
• Variable cost before advertising: $61
• Contribution before advertising: $120 − $61 = $59
• Contribution margin: $59 ÷ $120 × 100 = 49.17%

The list price should not replace collected revenue in this calculation. Using $150 would report a misleading 59.33% margin even though the store retained only $120. For catalog or campaign planning, document how discounts, refunds and return allowances enter the calculation so the result can be reconciled later.

Turn contribution margin into break-even ROAS

Pre-ad contribution margin can be converted into the minimum revenue per advertising dollar required to cover variable costs and ad spend:

In the worked example, spending $59 to acquire one $120 order uses all $59 of pre-ad contribution. The maximum acquisition cost at advertising break-even is therefore $59. At a 2.03x ROAS, $59 of ad spend is associated with roughly $120 of revenue. Fixed overhead, tax and desired profit are still unpaid at that exact threshold.

Use the break-even ROAS calculator to enter the actual cost components and a profit target. The break-even ROAS margin table provides quick checks for common verified contribution margins. A target should normally sit above the break-even floor if the business needs room for fixed expenses, cash flow and profit.

Calculate maximum CPA from margin dollars

For a single order, the pre-ad contribution dollars represent the theoretical maximum customer acquisition cost at advertising break-even. In the example, maximum break-even CPA is $59. If the business wants to retain $12 after advertising, allowable acquisition cost becomes $59 − $12 = $47.

This shortcut is reliable only when the order value and variable costs represent the customers being acquired. A blended average can hide low-margin products, discounts or new-customer return behavior. The maximum CPA guide shows how to extend the calculation to leads, conversion rates and controlled lifetime-value assumptions.

Product margin versus blended margin

For a period with several products, add contribution dollars first and divide by total net revenue. Do not take a simple average of percentages unless every product contributes the same revenue. Suppose Product A produces $8,000 of revenue at 60% contribution margin and Product B produces $2,000 at 20%. Their contributions are $4,800 and $400, for $5,200 total. Blended margin is $5,200 ÷ $10,000 = 52%, not the simple average of 40%.

Campaign mix can shift this number even when each product's unit economics stay unchanged. Recalculate when discounts, shipping policies, payment fees, fulfillment rates, product mix or return behavior change. Use mature refund data where possible instead of assuming the first-day order value is final.

Period-level example and reconciliation

Assume a monthly report shows $80,000 in net collected revenue and $46,000 in matching pre-ad variable costs. Contribution is $34,000 and contribution margin is 42.5%. Break-even ROAS is 1 ÷ 0.425 = 2.35x. If the advertising platform reports 3.0x ROAS, that is above the calculated floor, but it does not prove total business profit. Attribution may claim revenue that another channel also receives credit for, and fixed payroll, software and overhead still need coverage.

Compare revenue efficiency with profit using the ROAS versus ROI framework. ROAS divides attributed revenue by ad spend; margin measures what remains under a stated cost definition. Keeping those metrics separate prevents a healthy-looking revenue ratio from being presented as net profit.

Edge cases and input checks

• Revenue equals cost: profit and margin are 0%.
• Cost exceeds revenue: margin is negative, indicating a loss under the chosen cost definition.
• Revenue is zero: margin is undefined because the formula would divide by zero.
• Cost is zero: margin can be 100%, while markup cannot be meaningfully calculated because markup divides by cost.
• Negative inputs: refunds, credits and accounting adjustments need a separate reconciliation rather than being entered casually as a negative selling price or cost.
• Mixed time periods: a month of costs cannot be compared with one week of revenue.

The calculator is a planning tool. Its output is only as complete as the cost definition. Save the assumptions beside the result, especially when finance, ecommerce and media teams use different labels for revenue, product cost or contribution.

Reviewed October 6, 2026 · By ROAS Lab Editorial Team

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