TOOLGENIEPercentage Calculator
Calculate percentages, find what percent one number is of another, or compute percentage change — with step-by-step solutions
Calculation Mode
How to Use the Percentage Calculator
- Select your calculation mode — choose from "What is X% of Y?", "X is what % of Y?", "Percentage increase/decrease", or "Percentage change".
- Enter your numbers — use whole numbers or decimals (e.g., 15, 12.5, or 0.25). The tool supports decimal percentages for precise calculations.
- Click Calculate to see the result and a step-by-step breakdown of how the answer was derived.
- Use the step-by-step solution to understand the math behind the percentage calculation and verify your work.
About the Free Percentage Calculator
The Percentage Calculator by ToolGenie is a free, browser-based tool that performs percentage calculations instantly. Whether you need to find what percent one number is of another, calculate a percentage of a value, or determine percentage increase or decrease between two numbers, this tool provides accurate results with clear step-by-step solutions.
Every calculation runs entirely in your browser. No data is sent to any server or stored anywhere. Your numbers stay private and secure on your device.
The calculator supports decimal percentages for precise calculations and is ideal for students, professionals, and anyone who needs to work with percentages in everyday life — from discounts and tips to data analysis and financial planning.
Frequently Asked Questions (FAQ)
How do I calculate what is X percent of Y?
Select the "What is X% of Y?" mode, enter your percentage (X) and whole number (Y), then click Calculate. The formula is (X ÷ 100) × Y. For example, 15% of 200 = (15 ÷ 100) × 200 = 30.
How do I find what percent one number is of another?
Use the "X is what % of Y?" mode. Enter the part (X) and the whole (Y), then click Calculate. The formula is (X ÷ Y) × 100. For example, 25 is 25% of 100 because (25 ÷ 100) × 100 = 25.
How do I calculate percentage increase or decrease?
Select "Percentage increase/decrease" or "Percentage change". Enter the original value and the new value. The formula is ((New − Original) ÷ Original) × 100. A positive result means an increase; a negative result means a decrease.
Does the percentage calculator support decimal percentages?
Yes. You can enter decimal percentages such as 12.5%, 0.25%, or 33.33%. The tool handles all decimal values for precise calculations in finance, science, and everyday use.
Is this percentage calculator free and safe to use?
Yes. The tool is completely free with no signup required. All calculations run in your browser — no data is sent to servers or stored. Your numbers remain private and secure on your device.
When would I use a percentage change calculator?
Use it when comparing two values over time — for example, price changes, population growth, sales before and after a campaign, or stock performance. It shows how much a value increased or decreased as a percentage of the original.
Tips for Working with Percentages
- Discounts: To find sale price, calculate the discount (X% of original) and subtract it from the original price.
- Tips: Use "What is X% of Y?" with your bill total and desired tip percentage (e.g., 15% or 20%).
- Growth rates: Use percentage change to compare values over time — essential for investments and business metrics.
- Test scores: Use "X is what % of Y?" to find your score as a percentage of the total possible.
- Verify results: Use the step-by-step breakdown to double-check your manual calculations or learn the underlying formulas.