How to use
Enter a number, choose add or subtract, and enter the percentage. You’ll see the result and how much the percentage itself amounts to.
If the number already includes the increase (a price with tax, a salary with a bonus) and you need the original, choose “Remove a percentage already added”. 1,200 with 20% added is 1,000, not 960 — taking 20% off 1,200 is wrong, because the 20% was calculated on the smaller number.
Formulas
- Add a percentage:
number × (100 + percentage) / 100. - Subtract a percentage:
number × (100 − percentage) / 100.
Examples
- 1,000 + 20% = 1,200 (20% of 1,000 is 200).
- 1,000 − 20% = 800.
- $2,500 − 15% = $2,125: a $375 discount.
- $1,500 + 20% = $1,800.
FAQ
Why doesn’t adding 20% and then subtracting 20% give the original number? The second percentage is taken from the new number: 100 + 20% = 120, but 120 − 20% = 96.
How do I find the original number before a markup? Divide the total by (1 + percentage/100): if the price is $1,200 after a 20% markup, the original was 1,200 / 1.2 = $1,000. Subtracting 20% from $1,200 would give $960, which is wrong.
How do I find the percentage change between two numbers? Use the percentage change calculator. To find just X% of a number, use the percentage calculator.