Percentages are ubiquitous in daily life, used to calculate everything from store discounts and sales tax to financial interest rates and statistical probabilities. A percentage simply represents a number or ratio expressed as a fraction of 100. Accurately determining percentage changes, markups, or the original value before a percentage was applied is critical for sound financial decision-making, accounting, and data analysis.
Core Percentage Formulas
Find a Percentage: (Part / Whole) × 100
Percentage Change: ((New Value - Old Value) / |Old Value|) × 100
How to Use This Calculator
- Select the specific type of percentage calculation you need (e.g., "What is X% of Y?" or "Percentage increase from X to Y").
- Input the known numerical values into the appropriate fields.
- Click Calculate to instantly generate the exact percentage or numerical outcome.
Frequently Asked Questions (FAQ)
How do I calculate a percentage discount?
To calculate a discount, multiply the original price by the discount percentage (as a decimal). For example, a 20% discount on a $50 item is calculated as $50 × 0.20 = $10. Subtract the $10 from the original price to find the final cost ($40).
Is a 50% increase followed by a 50% decrease equal to the original amount?
No. If you start with $100 and increase it by 50%, you have $150. If you then decrease that $150 by 50%, you subtract $75, leaving you with $75. Percentage changes compound based on the *new* value, not the original starting point.