What is a Percentage Calculator?
A percentage calculator is a versatile mathematical tool that helps you solve common percentage problems quickly and accurately. Whether you need to calculate discounts while shopping, figure out tips at restaurants, determine percentage changes in data, or solve basic percentage equations, this free online calculator handles it all.
Percentages are fundamental to everyday life and business. From understanding sales tax and interest rates to analyzing statistics and financial reports, percentage calculations appear everywhere. Our calculator eliminates the need for manual calculations or complex formulas, giving you instant, accurate results with clear step-by-step breakdowns.
All calculations happen instantly in your browser with no data sent to any server. The calculator supports multiple percentage operations including finding a percentage of a number, determining what percentage one number is of another, calculating percentage increase or decrease, discount calculations, tip splitting, and adding/subtracting percentages from values.
How to Use This Calculator
Basic Percentage (X% of Y)
Enter the percentage and the number to find the result. For example, 20% of 150 equals 30. Perfect for calculating sales tax, tips, or discounts.
What Percent (X is what % of Y)
Find what percentage one number represents of another. For example, 30 is 20% of 150. Useful for test scores, completion rates, and comparisons.
Percentage Change
Calculate the percentage increase or decrease between two values. Shows if something went up or down and by how much. Great for tracking growth or decline.
Discount Calculator
Enter the original price and discount percentage to see the final price and savings. Perfect for shopping during sales and comparing deals.
Tip Calculator
Calculate tips and split bills among multiple people. Shows tip amount, total bill, and per-person cost. Your tip preferences are saved for next time.
Add/Subtract Percentage
Add or subtract a percentage from any value. For example, increase 100 by 25% to get 125, or decrease it to get 75. Useful for markup and margin calculations.
Common Use Cases
Shopping & Retail
Calculate sale prices, compare discounts (is 30% off or $50 off a better deal?), figure out sales tax, and determine final costs. When stores advertise "Buy one get one 50% off," quickly calculate your actual savings.
Finance & Business
Calculate profit margins, markup percentages, ROI (return on investment), year-over-year growth, and interest rates. Essential for financial analysis, pricing strategies, and business planning.
Education & Testing
Convert test scores to percentages, calculate GPA equivalents, determine grade thresholds, and figure out what score you need on the final exam to achieve your target grade.
Health & Fitness
Track weight loss or gain percentages, calculate body fat percentage changes, determine calorie intake percentages from macronutrients, and monitor fitness progress over time.
Data Analysis
Analyze survey results, calculate conversion rates, determine market share, compare year-over-year metrics, and understand proportions in datasets. Essential for reports and presentations.
Dining & Entertainment
Calculate tips at restaurants (15%, 18%, 20%), split bills fairly among friends, and figure out per-person costs including tax and tip. Make dining out stress-free.
Percentage Formulas Explained
Finding X% of Y: Multiply Y by X and divide by 100. Formula: (X × Y) ÷ 100. Example: 25% of 200 = (25 × 200) ÷ 100 = 50.
Finding what percent X is of Y: Divide X by Y and multiply by 100. Formula: (X ÷ Y) × 100. Example: 40 is what % of 200? = (40 ÷ 200) × 100 = 20%.
Percentage Change: Subtract the old value from the new value, divide by the old value, multiply by 100. Formula: ((New - Old) ÷ Old) × 100. Positive = increase, Negative = decrease.
Adding a Percentage: Multiply the original by (1 + percentage/100). Formula: Value × (1 + X/100). Example: 100 + 20% = 100 × 1.2 = 120.
Subtracting a Percentage: Multiply the original by (1 - percentage/100). Formula: Value × (1 - X/100). Example: 100 - 20% = 100 × 0.8 = 80.