Markup is the difference between selling price and cost, expressed as a percentage of cost. It is how many businesses set prices: take what an item costs and add a fixed percentage. Margin expresses the same dollar difference as a percentage of price, so the two numbers are never equal.
Markup = (price − cost) / cost × 100. To convert: margin = markup / (1 + markup), and markup = margin / (1 − margin).
An item costs $60 and sells for $80. The $20 difference is a markup of $20 / $60 = 33.3% and a margin of $20 / $80 = 25%. To reach a 40% margin on the same $60 cost, the markup must be 66.7%, giving a price of $100.
Confusing the two. A team told to hit 30% margin that applies a 30% markup prices at $78 on a $60 cost and earns only 23.1%. Discounts taken after the markup also erode it unseen. The full comparison is markup vs margin.