Calculate percentages, percentage changes, increases, and decreases instantly with our free online tool
Three essential percentage calculations: find percentage of a number, find what percentage one number is of another, and calculate percentage change.
Real-time calculations as you type. No need to click calculate buttons - results appear instantly with detailed explanations.
Each result includes a human-readable explanation showing the exact calculation performed, helping you understand the math.
Automatically identifies whether a change is an increase or decrease, with clear visual indicators and proper formatting.
Supports decimal inputs and provides precise results rounded to two decimal places for easy reading.
Completely free to use with no registration required. All calculations happen in your browser - your data never leaves your device.
To find what X% of Y is, multiply Y by X and divide by 100. For example, 20% of 150 = (150 × 20) / 100 = 30. Our calculator does this instantly - just enter the percentage and number in Mode 1.
To find what percentage X is of Y, divide X by Y and multiply by 100. For example, 30 is what % of 150? (30 / 150) × 100 = 20%. Use Mode 2 for this calculation.
Percentage change = ((New Value - Old Value) / Old Value) × 100. A positive result is an increase, negative is a decrease. For example, from 100 to 120: ((120 - 100) / 100) × 100 = 20% increase. Use Mode 3 for this.
A percentage increase occurs when the new value is greater than the original (positive change). A percentage decrease occurs when the new value is less than the original (negative change). Our calculator automatically identifies which one applies.
Yes! Our calculator supports decimal inputs for all fields. You can calculate things like "What is 12.5% of 87.3?" or find percentage changes between decimal values.
This is mathematically correct. For example, increasing from 100 to 120 is a 20% increase, but decreasing from 120 to 100 is a 16.67% decrease. This happens because the base (denominator) is different in each calculation.