Margin vs markup: the difference that decides your prices

Margin and markup are both expressed as percentages, both describe the gap between cost and price, and both get called "profit" in casual conversation. They are not the same number, and mixing them up is one of the most expensive small-business mistakes there is — because it always errs in the same direction: underpricing.

Two questions, two percentages

Markup answers: how much did I add to my cost? It is measured against the cost. Buy something for £40, sell it for £60, and you've applied a 50% markup — the £20 you added is half of the £40 you paid.

Margin answers: how much of my selling price is profit? It is measured against the price. On the same sale, the £20 profit is a third of the £60 price — a margin of 33.3%.

Same transaction, same £20 of profit, two different percentages. Neither is wrong; they measure against different bases. The trouble starts when a number from one world is used in the other.

Why the confusion always costs you money

Suppose your business plan needs a 50% margin to cover overheads and leave a profit. If you "add 50%" to your costs — a 50% markup — you actually achieve only a 33.3% margin. On £100,000 of annual sales, that's roughly £16,700 of gross profit you planned for and never collected. Because markup percentages are always bigger than the margin they produce, applying a margin target as a markup always leaves you short — never accidentally rich.

The gap grows fast at higher percentages. A 100% markup (buy for £50, sell for £100) is only a 50% margin. And a 100% margin is impossible unless your product costs nothing at all — which is a handy sanity check: if someone claims a margin above 100%, they mean markup.

Converting between them

Two one-line formulas cover every case:

Some common pairs, worth keeping to hand:

Which one should you work in?

Use markup when you're setting a price from a known cost — it's the natural direction for pricing labour and materials, and trades have long-standing customary markups for exactly this reason. Use margin when you're judging the health of a business — margins can be compared across products, months and competitors because they share a common base: the sales pound. Accountants, lenders and platforms like Amazon all report in margin, so your targets and covenants will almost always be stated that way.

The discipline that prevents mistakes is simple: write down which one a number is every time it changes hands ("50% margin target", "40% markup applied"), and convert deliberately rather than by feel.

A worked pricing decision

A candle maker's product costs £6.50 in materials and £2.50 in labour and packaging — £9 all-in. The business needs a 55% gross margin to cover fixed costs and profit. Applying the conversion, a 55% margin requires a markup of 55 ÷ 45 × 100 ≈ 122%. Price: £9 × 2.22 = £20. Had they "added 55%" instead, the price would have been £13.95 — a margin of just 35.5%, and a business that mysteriously never makes the profit its spreadsheet promised.