Percentage Off a Sale Price How can I find the percentage off of a sale price? For example, the sale price of an item is $\$13$. The original price was $\$85$. What _percentage_ was discounted from the original price? For example, the sale price of an item is $\$19$. The original price was $\$150$, which means the sale is $87\%$ off the original price.

Use the formula:

$\text{percent discount}=\frac{\text{difference}}{\text{original}}\times 100$

Thus: $\frac{150-19}{150}\times 100 = \frac{131}{150}\times 100 = 87\frac13$, so you get $87\frac13\%$

The same formula works for percent increases. It's always "difference over original".