Find a percentage of a number
Multiply the number by the percentage and divide by 100. To calculate 15% of 200, work out 200 × 15 ÷ 100 = 30. In the Toolbox, enter 15 in Percentage and 200 in Number, then choose Calculate.
Discount example
If an item costs 80 and has a 25% discount, the discount amount is 80 × 25 ÷ 100 = 20. Subtract the discount from the original price: 80 − 20 = 60. The calculator gives the percentage amount; it does not automatically subtract it from the original price.
Percentage change is another calculation
To find an increase from 50 to 60, subtract the original from the new amount, divide by the original and multiply by 100: (60 − 50) ÷ 50 × 100 = 20%. You cannot use this formula when the original value is zero. Do not confuse a percentage change with a difference in percentage points.
Check your result
10% is one tenth of a number and 50% is half. These quick estimates can help spot a misplaced decimal. The tool displays a rounded numerical result; check any required currency or accounting rounding separately.