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Profit margin vs. markup: why the denominator matters

Published by Navon Ventures S.A.S · October 20, 2026

Margin and markup both describe the gap between a selling price and an included cost. They use different denominators. Treating the percentages as interchangeable can turn an intended margin into a lower one, even when every multiplication is correct. Begin by identifying exactly which costs belong in your example.

One sale, two useful ratios

Suppose an item sells for $100 and its included cost is $60. The difference is $40. Margin compares that difference with revenue: 40 ÷ 100 × 100 = 40%. Markup compares it with cost: 40 ÷ 60 × 100 ≈ 66.67%. These are two descriptions of the same $40, not two different amounts of profit. Try those values in the profit margin calculator and markup calculator.

Adding a percentage does not create the same margin

If you add 40% to a $60 cost, the selling price becomes $84. The difference is $24, and the margin is 24 ÷ 84 ≈ 28.57%. To model a 40% margin on the same included cost, divide cost by one minus the target margin: 60 ÷ (1 − 0.40) = $100. A target margin of 100% cannot be achieved with a positive cost under this formula because the denominator becomes zero.

Use consistent cost definitions

A ratio based only on materials says something different from a ratio that includes labor, platform fees, overhead and other expenses. Our profit margin tool uses the total included costs you enter. It cannot determine whether a cost has been omitted or classify your accounting profit. Compare figures only when their cost definitions, currencies and time periods match.

Check the result before setting a price

Write down the selling price, included costs and difference as amounts before converting them into percentages. Check which denominator answers your question. Preserve precision while calculating and round only the displayed result. Demand, capacity, taxes and commercial terms can affect an actual price; this arithmetic does not decide them. For a separate model of the units needed to cover fixed costs, use the break-even calculator.