Percentage Calculator
Calculate percentages instantly — find what percent of a number, percentage change, increase or decrease, and reverse percentages.
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy
Percentage Calculator Formula
Percentage = (Part / Whole) x 100
Percentage expresses a number as a fraction of 100. To find X% of Y: Result = (X / 100) x Y. To find what percent X is of Y: Percentage = (X / Y) x 100. To compute percentage change between an original and a new value: Change = ((New - Old) / |Old|) x 100. A positive change is an increase; a negative change is a decrease. These three formulas cover the vast majority of real-world percentage problems, from calculating discounts and tax amounts to comparing wages and interpreting grade scores.
Percentage Calculator — Worked Examples
Example 1: Finding a percentage of a number
Problem:What is 15% of 240?
Solution:Multiply 240 × 0.15 (15 ÷ 100 = 0.15)
Result:240 × 0.15 = 36. So 15% of 240 is 36.
Example 2: Percentage change (increase)
Problem:A product's price rose from $80 to $92. What is the percentage increase?
Solution:Percentage change = ((New − Old) ÷ Old) × 100 = ((92 − 80) ÷ 80) × 100
Result:(12 ÷ 80) × 100 = 15% increase
Example 3: Reverse percentage (find the original)
Problem:After a 20% discount, an item costs $64. What was the original price?
Solution:Original = Discounted Price ÷ (1 − discount rate) = 64 ÷ 0.80
Result:64 ÷ 0.80 = $80 was the original price
Percentage Calculator — Frequently Asked Questions
How do I find what percentage one number is of another?
To find what percentage X is of Y, divide X by Y and multiply by 100. For example, 45 is what percent of 180? 45 / 180 = 0.25, then 0.25 x 100 = 25%. The formula is Percentage = (Part / Whole) x 100.
How do I calculate percentage change between two numbers?
Percentage change = ((New Value - Old Value) / |Old Value|) x 100. If the result is positive, it is an increase. If the result is negative, it is a decrease.
What is the difference between percentage and percentile?
A percentage is a fraction of 100 used to express a proportion, while a percentile indicates the position of a value within a distribution.
Why is percentage increase and decrease not symmetrical?
A 50% increase followed by a 50% decrease does not return to the original value because the base changes between the two calculations.