Markup: Markup is the amount added to a part's cost to reach its selling price, expressed as a percentage of the cost, so a 50% markup on a €40 cost gives a €60 price.
Markup is the way most shops actually build a price: work out the cost, then add a percentage on top.
markup = (price - cost) / cost
Example: a print costs €40 in machine time, material and labour. With a 50% markup, you add €20 and sell it for €60. The margin on that sale is €20 / €60, about 33%.
Markup is easy to apply, which is why it is popular in spreadsheets and quoting tools. The trouble starts when it gets mixed up with margin. The same €20 profit is a 50% markup but a 33% margin. If your business plan says “35% margin” and your spreadsheet adds 35% to cost, you are under-pricing every job.
Quick conversions worth remembering: a 25% markup is a 20% margin, a 50% markup is a 33% margin, and a 100% markup (doubling the cost) is a 50% margin.
Another trap is applying markup to a cost that leaves out overhead. Then the markup is quietly paying the rent, and the real profit is much smaller than it looks. This approach to pricing as a whole is called cost-plus pricing. For worked comparisons, read margin vs markup.
Go deeper: Margin vs markup for manufacturers, with a conversion table