Percentage Calculator
Choose a calculation mode to find a percentage of a number, express one number as a percentage of another, or find the percentage change between two values.
How It Works
Each mode uses a different rearrangement of the same underlying relationship between a part, a whole and a percentage. Percentage change additionally compares an original value to a new one and expresses the difference relative to the original.
Formula
X% of Y = (X ÷ 100) × Y. X is what percent of Y = (X ÷ Y) × 100. Percentage change = ((New − Original) ÷ |Original|) × 100.
Example
20% of 150 is 30. 30 is 20% of 150. Going from 150 to 180 is a 20% increase.
Frequently Asked Questions
- Can percentage change be negative?
- Yes, a negative result means the new value is smaller than the original, representing a percentage decrease.
- Why can't the whole value be zero?
- Dividing by zero is mathematically undefined, so "what percent of zero" has no meaningful answer.
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