Markup and Margin Conversion

Since markup and margin describe the same transaction from two directions, converting between them is pure algebra: $m = g/(1-g)$ one way and $g = m/(1+m)$ the other. A 20% margin is a 25% markup. A 50% markup is a 33.3% margin. A 100% markup, the old "keystone" pricing of retail, is a 50% margin.

Keep three landmarks in your head and you will rarely be badly wrong: 20% margin equals 25% markup, 33% margin equals 50% markup, 50% margin equals 100% markup. Markup is always the larger number, and the gap widens fast as profitability rises. At a 60% margin the markup is 150%.

This is worth a laminated card by the estimating desk. A supplier quoting you in markup and a banker quoting you in margin are describing the same job, and the only way to argue with either of them is to speak both languages fluently.