Math

Percentage Calculator

Multiple percentage calculations in one tool: find percentages, increases, decreases, and more.

What is X% of Y?
What is % of =
X is what % of Y?
is what % of =
Percentage Change (Increase/Decrease)
From to =
Increase or Decrease a Number by %
by % =

How to Calculate Percentages

A percentage is a fraction of 100. The word "percent" comes from the Latin "per centum," meaning "per hundred." Percentages are used everywhere: discounts, taxes, grades, statistics, and financial calculations.

Basic Percentage Formulas

QuestionFormulaExample
What is X% of Y?Result = Y × (X / 100)25% of 200 = 200 × 0.25 = 50
X is what % of Y?% = (X / Y) × 10050 is what % of 200? = (50/200) × 100 = 25%
% Change from A to B% = ((B - A) / A) × 100From 80 to 100 = ((100-80)/80) × 100 = 25%
Increase X by Y%Result = X × (1 + Y/100)200 + 15% = 200 × 1.15 = 230
Decrease X by Y%Result = X × (1 - Y/100)200 - 15% = 200 × 0.85 = 170

Common Percentage Conversions

To convert a percentage to a decimal, divide by 100 (e.g., 25% = 0.25). To convert a decimal to a percentage, multiply by 100 (e.g., 0.75 = 75%). To convert a fraction to a percentage, divide the numerator by the denominator and multiply by 100 (e.g., 3/4 = 0.75 = 75%).