Choose a calculation type to get started.
Example: What is 20% of 150?
Example: What percent is 30 of 120?
Example: Change from 100 to 125.
Example: What's the original value if 100 is 25% more?
Percentages are simply fractions expressed out of 100, making them a universal way to compare proportions and changes. The four fundamental percentage calculations each serve different purposes: finding a percentage of a number helps determine parts of a whole (like calculating tips or discounts), determining what percentage one number is of another allows you to express relationships as comparable ratios, percentage change reveals how much something has increased or decreased relative to its starting value, and finding the original value lets you work backwards from a final result to discover the starting point. These calculations form the foundation of countless real-world applications, from analyzing data trends and calculating interest rates to determining sale prices and measuring growth rates in business and science.