Percentage Calculator
Calculate percentages instantly — find a percentage of a number, determine what percent one number is of another, or calculate percentage change.
What is X% of Y?
X is what % of Y?
Percentage Change from X to Y
About Percentage Calculator
Our free Percentage Calculator makes it easy to solve three of the most common percentage problems. Whether you need to calculate a discount, figure out a tip, determine a tax amount, or analyze percentage changes in data, this tool provides instant, accurate results.
The calculator supports three modes: finding what a given percentage of a number is (useful for discounts and taxes), determining what percentage one number is of another (useful for grades and ratios), and calculating the percentage change between two values (useful for growth rates and comparisons).
All calculations are performed instantly in your browser using JavaScript. No data is sent to any server, and results are displayed immediately as you click calculate. Works on all devices including mobile phones and tablets.
Frequently Asked Questions
Q How do I calculate a percentage of a number?
To calculate X% of Y, multiply Y by X and divide by 100. For example, 25% of 200 is (200 × 25) ÷ 100 = 50. Our calculator handles this automatically — just enter the values and click Calculate.
Q How do I calculate percentage change?
Percentage change is calculated as ((New Value - Old Value) / Old Value) × 100. A positive result indicates an increase, while a negative result indicates a decrease. For example, going from 80 to 100 is a 25% increase.
Q What are common uses for percentage calculations?
Percentage calculations are used for discounts and sales, tax calculations, tip amounts, interest rates, grade calculations, statistical analysis, financial growth rates, nutritional information, and virtually any situation involving proportional comparisons.