Markup is the ratio of profit to the cost of production or purchase, expressed as a percentage. Unlike margin, the base is cost, not selling price.
Markup = (Price − Cost) ÷ Cost × 100%
Cost: $80 · Price: $100
Markup = (100 − 80) ÷ 80 × 100% = 25%
Note: same $20 profit = 20% margin but 25% markup.
Calculate it yourself
Use the margin & markup calculator.