Markup is not margin: the mistake that underprices everything you sell

You buy something for $100 and sell it for $150. You made $50. Everyone agrees on that part.

The disagreement is what to divide it by. Divide the $50 by what the item cost you and you get 50% — that is markup. Divide it by what you sold it for and you get 33.3% — that is margin.

Both numbers are correct. They describe the identical transaction. And because margin divides by the larger number, margin is always the smaller of the two — for every product, at every price, without exception.

That last point is the whole reason this matters. If someone tells you they work on 40%, and you do not know which one they mean, you do not know their prices.

Here is the mistake in its usual form. A shop buys an item for $60 and wants a 40% margin on it. Someone adds 40% to the cost — $60 × 1.40 — and prices it at $84.

That is not a 40% margin. At $84 the profit is $24, and $24 out of $84 is a 28.6% margin. To actually make 40% the price needed to be $100, because 40% margin means the cost has to be 60% of the price: $60 ÷ 0.60 = $100.

The shop has given away $16 on every single unit, and nothing in its own figures will flag it. The item sold. It made a profit. The margin report just comes in lower than expected and nobody can say why.

On a hundred units a month that is $19,200 a year, on one product, from one wrong multiplication.

The two are related by simple algebra, and the relationship is not linear — which is why nobody can do it in their head reliably.

To go from markup to margin: margin = markup ÷ (1 + markup). To go the other way: markup = margin ÷ (1 − margin).

The table below is the one worth keeping. A few of these are worth memorizing outright — particularly that a 50% margin means doubling your cost, which surprises people who assumed 50% meant adding half.

Markup can be any number at all. A 900% markup is unusual but perfectly coherent — it means selling something for ten times what it cost you, which plenty of businesses do.

Margin cannot reach 100%. A 100% margin would mean the profit equals the entire selling price, which means the item cost nothing. As margin climbs toward 100 the required markup runs away to infinity: 90% margin needs a 900% markup, 99% would need 9,900%.

This asymmetry is a useful sanity check. If someone quotes you a margin above 100%, they mean markup. If they quote a markup of 30% and call it a margin, they are underpricing by the gap in the table above.

Use margin when you are setting prices and when you are reporting performance. It is the share of revenue you keep, which makes it directly comparable across products with different costs, and it is what every profit and loss statement is built from. A 30% margin means the same thing whether the item cost $5 or $5,000.

Use markup when you are working forwards from a known cost, which is how most trade and retail pricing is actually done. A builder quoting materials plus 20% is using markup, and that is the natural way to think when the cost is the number in front of you.

The trouble is not that one is right. It is that the two get used in the same conversation without either party saying which. A supplier talking about markup and a finance team talking about margin can both say "we work on 40%" and mean prices that differ by a fifth.

The fix is boringly simple: say which one you mean, every time, and write the denominator down.

Everything above uses the cost of the goods themselves. It says nothing about whether the resulting profit covers your rent, wages or insurance — that is a different question, and the Break-Even Calculator is the one that answers it.

Gross margin is also not contribution margin. Contribution counts only the costs that vary with each unit sold; gross margin often absorbs some fixed overhead by convention. Using a gross margin figure in a break-even calculation understates the units you need, sometimes badly.

And none of it tells you what the market will pay. Pricing from cost is arithmetic; pricing from what a customer values is a business decision, and the second one is usually worth more than the first.