Introduction
The Percentage Calculator is a comprehensive free online tool that handles all your percentage calculation needs. Whether you need to calculate basic percentages, percentage changes, reverse percentages, or increase/decrease values by a percentage, this tool provides instant accurate results.
How to Use
Using the Percentage Calculator is simple: 1) Select the calculation type you need. 2) Enter the required values in the input fields. 3) Results update automatically as you type. 4) Click the copy button to copy results to clipboard.
Features
- •Basic percentage calculation: Find what X% of Y is
- •Percentage change calculator: Calculate increase/decrease percentage between two values
- •Reverse percentage: Find the total when you know a value and its percentage
- •Value increase/decrease: Calculate what happens when you add or subtract a percentage
- •Instant results with real-time calculation
- •One-click copy to clipboard for all results
- •Works on all devices - desktop, tablet, and mobile
- •Completely free with no registration required
Percentage Formula Reference
Quick reference guide for common percentage calculations
| Calculation Type | Formula | Example |
|---|---|---|
| Basic Percentage | (A × B) / 100 | 20% of 150 = 30 |
| Percentage Increase | ((New - Old) / Old) × 100 | 50 to 75 = 50% |
| Reverse Percentage | (Value × 100) / Percent | 40 is 20% of 200 |
| Value + X% | A × (1 + X/100) | 100 + 15% = 115 |
| Value - X% | A × (1 - X/100) | 100 - 15% = 85 |
Frequently Asked Questions
How do I calculate percentage increase?
To calculate percentage increase: 1) Subtract the original value from the new value. 2) Divide the difference by the original value. 3) Multiply by 100. Formula: ((New - Original) / Original) × 100. For example, from 50 to 75: ((75-50) / 50) × 100 = 50% increase.
How do I manually calculate a discount?
To calculate a discount: 1) Multiply the original price by the discount percentage. 2) Divide by 100. 3) Subtract from original price. For example, 20% off $100: (100 × 20) / 100 = $20 discount, so final price is $80.
What is the reverse percentage formula?
Reverse percentage finds the total when you know a part and its percentage. Formula: Total = (Part × 100) / Percentage. For example, if $40 is 20% of the total, then: (40 × 100) / 20 = $200 total.
How do I calculate year-over-year growth rate?
Year-over-year (YoY) growth rate uses the percentage change formula: ((Current Year - Previous Year) / Previous Year) × 100. For example, if revenue went from $100K to $120K: ((120-100) / 100) × 100 = 20% YoY growth.
Can I use this calculator for negative percentages?
Yes, the calculator handles negative percentages. A negative percentage change indicates a decrease, while a positive percentage indicates an increase.