Online Percentage Calculator
Calculate what is X% of Y, find percentage increases and decreases, and add or subtract percentages instantly with live formulas.
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Formula
This page covers four calculations: percentage of a value = (percent ÷ 100) × value; one value as a percent of another = (part ÷ whole) × 100; percentage change = ((new − old) ÷ |old|) × 100; and adding or subtracting a percent = base × (1 ± percent ÷ 100). Percentage change from a zero starting value is undefined.
Worked example
15% of 240 is 36. A change from 100 to 125 is a 25% increase; a change from 100 to 75 is a 25% decrease.
What the result means
A percentage compares a value to a base of 100. For percentage change, the sign indicates direction and the absolute starting value is the comparison base.
How to Use Percentage Calculator
Select Formula
Choose percentage of value, change, or fraction.
Type Numbers
Results update automatically in real-time.
Copy Result
1-click copy calculated answers.
Key Features & Benefits
Multi-formula
Covers all 4 common percentage calculations.
Instant
Zero page reloads or delays.
Frequently Asked Questions
How do I calculate percentage increase?
Formula: ((New Value - Old Value) / Old Value) × 100.
Key terms
- Percentage
- A number or ratio expressed as a fraction of 100.