How this calculator works
A percentage is a fraction out of 100. Use the first option to find a share of a number, such as a 15% tip or 30% discount; the second to see how large one value is compared with another; and the last three for markups, discounts and growth rates.
Formula
X% of Y = X ÷ 100 × Y. Percent change = (new − old) ÷ |old| × 100.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 15% of 200 is 0.15 × 200 = 30.
How do I calculate percentage change?
Subtract the old value from the new value, divide by the old value and multiply by 100. A negative result is a decrease.
How do I take a discount off a price?
Use "Decrease Y by X%". A 20% discount on $250 gives $200.