Percentage Calculator

Three everyday percentage questions, answered with the working shown.

Answer

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How this was calculated
Runs in your browser. Nothing you type is sent anywhere.
About the Percentage Calculator
Percentage Calculator answers the three questions people ask most: what is X% of Y, what percentage is X of Y, and the percentage change from one number to another. Every answer shows the calculation, so you can check it.
How to use it
  1. Pick the question.
  2. Enter the two numbers.
  3. Read the answer and the working.
Example
15% of 200 is 30. 30 is 15% of 200. Going from 80 to 100 is a 25% increase.
Questions
How is percentage change worked out?
(new − old) ÷ old × 100. From 80 to 100: (100 − 80) ÷ 80 × 100 = 25%.
Why is a 50% drop then a 50% rise not back to the start?
The rise is a percentage of the smaller number. 100 down 50% is 50, and 50 up 50% is 75.
Can I use negative numbers?
Yes. Percentage change uses the size of the starting number, so going from −50 to −25 shows a 50% change.