How do I calculate profit margin?
Profit margin is profit divided by selling price (for a unit) or by revenue (for a period). First compute profit: price minus all relevant costs. Then Margin = Profit ÷ Price. A 20% margin means you keep $0.20 of every $1 of sales after those costs. CrossKit’s Profit Calculator estimates the profit input so you can derive margin without mixing up markup.
Markup is profit ÷ cost. Margin is profit ÷ price. Mixing them makes a 25% conversation meaningless.
Steps
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Compute profit with a complete cost list
Incomplete costs inflate margin.
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Divide by price, not by cost, if you mean margin
Say “markup” if you divide by cost.
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Express as a percentage
0.18 is 18%. Do not report 18 as $18.
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Compare like with like
After-ad margin vs fee-only margin are different products.
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Recalculate after discounts
Percentage-off hits margin harder than beginners expect.
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Label the metric on every screenshot
Write “after-ad margin on price” on the chart. Future you will not remember which costs were included.
Margin vs markup, in one sentence each
Margin is Profit ÷ Price (or revenue). Markup is Profit ÷ Cost. A 20% margin means you keep $0.20 of every $1 of sales after the costs you included. Mixing them makes a “25%” conversation meaningless. Compute profit with a complete cost list first—incomplete costs inflate margin. Express the result as a percentage: 0.18 is 18%, not $18. Compare after-ad margin with after-ad margin, not with fee-only margin. Recalculate after discounts; percentage-off hits margin harder than beginners expect. CrossKit Profit Calculator estimates the profit input so you can divide by price without mixing up markup.
What is a “good” ecommerce margin?
It depends on ads and inventory turns. Many shops treat mid-teens after ads as a warning; some volume businesses accept less. Judge cash and inventory risk together. Gross margin is usually after COGS only; net is after almost everything—be explicit in team chat. Do not benchmark against a random tweet. Category and ad intensity dominate; use your own history. Amazon, Shopify and TikTok Shop all use the same margin definition; only the cost lines change.
How CrossKit fits this job
Get profit from CrossKit’s Profit Calculator, then divide by selling price. Label the screenshot “after-ad margin on price” so nobody treats markup as margin. The same inputs work for Amazon, Shopify and TikTok Shop; only the fee names change.
Example
Cost $40, price $100, profit $60 if no other costs: margin 60%, markup 150%. Add $25 ads: profit $35, margin 35%, markup 87.5%. Same SKU, three different stories. Label which one you mean.
Common mistakes
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Calling markup “margin” in a team chat
Purchasing and marketing will optimize different numbers.
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Benchmarking against a random tweet
Category and ad intensity dominate. Use your cohort.
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Reporting 40% margin when you divided profit by cost
That is markup. Purchasing will over-order and marketing will under-price if the label is wrong.
Recommended tool
Profit Calculator
Get profit from CrossKit’s calculator, then divide by price for margin. Works for Amazon, Shopify and TikTok Shop inputs.
Frequently Asked Questions
What is a good profit margin for ecommerce?
It depends on ads and turns. Many shops treat mid-teens after ads as a warning; some volume businesses accept less. Judge cash and inventory risk together.
Gross vs net margin?
Gross usually after COGS only. Net after (almost) everything. Be explicit.
Should I use selling price or revenue including shipping?
Use the amount the customer paid for the unit you are modeling. If shipping is charged separately and you keep it, decide whether it is in the denominator consistently.
Why did margin fall more than the coupon percent?
Because inbound, fulfillment and often ads did not fall by the same percent. Always recompute profit on the discounted price.