Percentage Calculator

Free Percentage Calculator Online

A versatile percentage calculator with three modes: calculate X% of a number, find what percentage one number is of another, or compute percentage change between two values.

The tool offers three calculation modes. Mode 1: "What is X% of Y?"—enter the percentage and the number to find the result. Mode 2: "X is what % of Y?"—enter two numbers to find what percentage the first is of the second. Mode 3: "Percentage change from X to Y"—enter the original and new values to calculate the percentage increase or decrease. Select your desired mode, fill in the input fields, and the result appears instantly as you type. All calculations update in real-time without requiring a calculate button.

Shoppers calculate discounts during sales to determine final prices after percentage-off promotions. Financial analysts compute percentage changes in stock prices, revenue, or other metrics. Students solve percentage problems for math homework or standardized tests. Budget planners determine what percentage of income goes to various expense categories. Sales teams calculate commission amounts as percentages of sales figures. Nutrition trackers determine what percentage of daily values are met by food portions.

For percentage of a number (X% of Y), the formula is (X/100) × Y. For "what percentage" calculations (X is what % of Y), it's (X/Y) × 100. Percentage change is calculated as ((New - Old) / Old) × 100, where negative results indicate decreases. When comparing percentage changes, remember that a 50% increase followed by a 50% decrease doesn't return to the original value. For financial calculations, understand the difference between percentage points and percentages—interest rising from 2% to 3% is a 1 percentage point increase but a 50% percentage increase. Round percentages appropriately based on context: 2-3 decimal places for precision, whole numbers for general communication.

All processing happens directly in your browser. Your files never leave your device — no server uploads, no cloud storage, no data retention. The tool works offline once loaded, requires no registration, and is completely free with no usage limits.