Choose the right percentage mode for a price comparison
Name the question
Ask whether you need a change between two values, a percentage of an amount, or a final price after a discount. These are related calculations but return different quantities. Choosing the right mode matters more than entering a large amount of precision.
Calculate percentage change
Enter original 80 and new value 100 in change mode. The result is 25%, from (100 − 80) ÷ 80 × 100. Reversing the pair gives −20% because the new base is 100. This mode requires an original value greater than zero.
Calculate a portion
For 15% of 200, choose percentage-of mode and enter base 200 and percentage 15. The result is 30. This amount can represent a reduction, share or other portion, but it is not automatically the amount remaining after subtraction.
Calculate a final discounted value
With price 200 and discount 15%, discount mode returns 170 and displays the reduction of 30. Discounts must be between 0 and 100%. For successive discounts, use the previous remaining price as the next base instead of simply adding the percentages.
Use the result appropriately
Review the displayed formula and mode before copying the value. The tool does not select a currency, add tax or apply invoice rounding rules. Results are displayed with limited decimal places for readability; treat the underlying question and any required rounding convention separately.
Try and verify the workflow
A change from 80 to 100 is a 25% increase because the difference, 20, is divided by the original value, 80.
Open percentage calculator