Calculator Tools/Percentage Calculator
Percentage Calculator
Calculate percentages, percentage change, and discounts
Input
%
Formula: A × B% = ?
Result
Enter a value
Percentage Calculator Guide
Learn how to calculate percentages effectively
What is Percentage Calculator?
The Percentage Calculator helps you perform various percentage calculations including basic percentages, ratios, percentage changes, and discounts. Essential for shopping discounts, financial calculations, grade computations, and business analytics.
How to Use
- Select a calculation mode (Basic, Ratio, Change, or Discount)
- Enter the required values in the input fields
- View the result instantly calculated
- Switch between modes for different percentage calculations
Practical Tips
- Basic mode: Calculate "X% of Y" - great for discounts and tips
- Change mode: Find percentage increase/decrease between two values
- Discount mode: Quickly calculate sale prices with markup or discount
Accuracy & Limitations
Results are calculated with high precision and displayed with up to 2 decimal places. All calculations happen instantly in your browser - no data is sent to any server.
Frequently Asked Questions
How do I calculate what percentage one number is of another?
Use the 'Ratio Calculation' mode. Enter the part value (A) and total value (B), and the calculator will show you (A/B) × 100. For example, if you scored 85 out of 100, enter 85 as part value and 100 as total value to get 85%.
How do I calculate percentage increase or decrease?
Use the 'Percentage Change' mode. Enter the original value and the new value. The formula is ((New - Original) / Original) × 100. A positive result indicates an increase, negative indicates a decrease. For example, if a price went from $100 to $120, that's a 20% increase.
What's the difference between discount and markup?
Discount reduces a price by a percentage (original × (1 - rate/100)), while markup increases it (original × (1 + rate/100)). For example, a 20% discount on $100 gives $80, while a 20% markup gives $120.
How do I reverse-calculate the original price from a discounted price?
To find the original price when you know the discounted price and discount rate, divide the discounted price by (1 - discount rate/100). For example, if an item costs $80 after a 20% discount, the original was $80 ÷ 0.8 = $100.
Why are some percentage results showing as negative?
Negative percentages in the Change mode indicate a decrease. If you calculate the change from 100 to 80, you'll get -20% because the value decreased by 20%. This is mathematically correct and commonly used in financial contexts.