Mastering Percentages
Percentages are a fundamental part of everyday life, from calculating a discount at a store to understanding statistics in the news. A percentage is simply a number or ratio expressed as a fraction of 100. While the concept is simple, the calculations can sometimes be tricky. This percentage calculator is designed to handle the most common percentage problems with ease, providing clear and accurate results for students, professionals, and anyone in between. Beyond percentages, you might also find our Fraction Calculator and Average Calculator useful for other common math problems.
Common Percentage Calculations Explained
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1. How to find a percentage of a number
This is the most common use case, perfect for calculating tips, sales tax, or discounts. Our Discount Calculator can handle these scenarios with even more detail. To solve "What is X% of Y?", you convert the percentage to a decimal and multiply by the base number.
Formula: (Percent / 100) * Base
Example: What is 20% of 300? → (20 / 100) * 300 = 0.20 * 300 = 60
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2. How to find what percentage one number is of another
This calculation is useful for comparing two numbers, like figuring out what portion of your income goes to rent. To solve "X is what percent of Y?", you divide the part (X) by the whole (Y) and multiply by 100.
Formula: (Value / Total) * 100
Example: 50 is what percent of 200? → (50 / 200) * 100 = 0.25 * 100 = 25%
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3. How to calculate percentage change
This is essential for tracking changes over time, such as stock price movements or business growth. To find the percentage increase or decrease, you find the difference between the new and old values, divide by the original value, and multiply by 100.
Formula: ((New Value - Old Value) / |Old Value|) * 100
Example: What is the percentage increase from 120 to 150? → ((150 - 120) / 120) * 100 = (30 / 120) * 100 = 25% increase