How to Calculate Profit Margin
A step-by-step guide to calculating profit margin correctly, including examples, common mistakes, and business use cases.
Quick answer
To calculate profit margin, subtract costs from revenue to find profit, then divide profit by revenue and multiply by 100. The key is choosing the right cost level: gross margin, contribution margin, and net margin answer different questions.
Step-by-step formula
Profit margin = (Revenue - Costs) ÷ Revenue × 100
| Step | Action | Example |
|---|---|---|
| 1 | Start with revenue | £50 selling price |
| 2 | Subtract relevant costs | £30 total cost |
| 3 | Find profit | £20 profit |
| 4 | Divide by revenue | £20 ÷ £50 |
| 5 | Convert to percentage | 40% margin |
Margin vs markup
Margin and markup are often confused. If a product costs £30 and sells for £50, the profit is £20. Margin is £20 ÷ £50 = 40%. Markup is £20 ÷ £30 = 66.7%. They describe the same sale from different bases, but they are not interchangeable.
Which costs to include
For gross margin, include direct cost of goods. For contribution margin, include variable selling costs such as payment fees, shipping, platform fees, and advertising per sale. For net margin, include wider business overheads. The right version depends on the decision you are making.
Common mistakes
- Using cost as the denominator when calculating margin.
- Ignoring payment fees.
- Ignoring platform fees.
- Leaving out ad spend.
- Averaging all products together and missing weak items.
- Using revenue before discounts and refunds.
Practical use
Use margin to set prices, compare products, decide ad budgets, evaluate discounts, and spot products that are busy but not profitable. A healthy business needs both sales and margin; one without the other is fragile.
FAQ
What is the profit margin formula?
Profit margin = profit divided by revenue, multiplied by 100.
Is margin the same as markup?
No. Margin is profit as a percentage of selling price. Markup is profit as a percentage of cost.
Should shipping be included?
If shipping is a cost to the business, include it in the relevant profit calculation.
Should ads be included?
For true net or contribution margin, yes.
Can margin be negative?
Yes. If costs exceed revenue, margin is negative.
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Educational note: CalcBeacon guides explain calculations and help you compare scenarios. They are not personal financial advice. For major borrowing, tax, pension, investment, or legal decisions, check the details with a qualified professional.