A $100 item marked 50% off sells for $50. To get back to $100 you need 100% markup, not 50%. The percentages work on different bases, so they don't cancel each other.
The math
Discount: percentage off the selling price. $100 − 50% = $50.
Markup: percentage added to the cost. $50 + 50% = $75 (not $100).
To get from $50 back to $100, you need $50 of profit on a $50 cost — a 100% markup. The same dollar amount ($50) is 50% of $100 but 100% of $50.
The conversion table
- 50% markup = 33% margin/discount
- 100% markup = 50% margin/discount
- 200% markup = 67% margin/discount
- 300% markup = 75% margin/discount
- Infinite markup → 100% margin (but impossible)
Why retail uses 100% markup
Called "keystone pricing". Wholesale × 2 = retail. The math is instant, the margin lands at 50% (good for operations and profit), and the customer can't easily reverse-engineer what the store paid. Most apparel, jewelry, and gift retail uses keystone or higher.
For pricing decisions
If you know your cost and want a target margin, use selling price math: price = cost / (1 - margin%). If you know your cost and want a target markup, use price = cost × (1 + markup%). Easy to confuse, easy to underprice if you do.
Cost + markup % → selling price + profit. Margin also shown for the other side of the coin.