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Free Percentage Calculator Tool

Percentage Calculator is a free online tool to help you calculate percentages.

What is % of
0
%
is what percent of
0
%
What is the percentage increase/decrease
from to
0
%

How to Use the Percentage Calculator

Our powerful tool handles the three most common percentage problems quickly and accurately. Simply enter your values into the corresponding fields and click "Calculate".

  • Case 1: Finding the Part - Use this to find a percentage of a given number (e.g., finding the discount amount).
  • Case 2: Finding the Rate - Use this to find what percentage one number is of another (e.g., finding your test score percentage).
  • Case 3: Finding Change - Use this to find the percentage increase or decrease between two numbers (e.g., tracking stock price changes).

How This Percentages Calculators Work: The Formula Explained

Here are the formulas and explanations used for each calculation:

Calculator 1. What is X% of Y?

This is the classic percentage question, here is an example and how it works:

Example: What is 20% of 150? You’re basically taking just a portion of a bigger number.

How it works: You convert the percentage into a decimal, then multiply it by the total.

Formula explained in simpler words: Take X, divide it by 100 to turn it into a percentage, then multiply by Y.

Result $= (X / 100) \times Y$

Calculator 2. X is what percent of Y?

Here you compare one number to another, see below how it works:

Example: 30 is what percent of 120? You’re asking: Out of the whole amount (Y), how big is X?

Formula explained in simpler words: Divide X by Y to see what fraction it is, then multiply by 100 to turn that into a percent.

Result $= (X / Y) \times 100$

Calculator 3. What is the percentage change from X to Y?

This one tells you how much something increased/decreased in percentage terms, with an example below:

Example: You went from 80 visitors to 100 visitors. How big was the increase?

Formula explained in easier words: First, the percentage calculator tool subtracts the old number (X) from the new one (Y). Then divides that difference by the old number. Finally, the tool multiplies by 100 to convert it into a percentage.

Result $= ((Y - X) / X) \times 100$