Percentage Calculator — Free Online Percentage Calculator
Calculate percentages, percentage changes, and differences. Supports multiple operations with instant results. All calculations happen locally — nothing leaves your browser.
How to Use the Percentage Calculator
- Select operation mode — choose from X% of Y, percentage change, difference, increase, or decrease.
- Enter values — input the relevant numbers for the selected operation.
- View results — see the answer instantly in the hero display and stat cards.
- Copy result — click the copy button to save the result to your clipboard.
Understanding Percentages
A percentage is a fraction expressed as a number out of 100. For example, 25% means 25 out of 100, or 0.25 as a decimal. Percentages are used everywhere from discounts and tax rates to test scores and financial growth.
The percentage change formula is: ((New - Old) / Old) × 100. This tells you how much something has increased or decreased relative to its original value.
Frequently Asked Questions
Use the "X% of Y" mode. Enter the tip percentage (e.g. 20) for X and the bill amount for Y. The result is your tip amount.
% change compares two values over time (old vs new). % difference compares two values without direction, using the average as the base: |A-B| / ((A+B)/2) × 100.
Yes, use the result of one calculation as input for the next. For example, to apply a 10% discount then add 8% tax, first calculate the discounted price, then use that as the base for the tax calculation.
Use Cases
Tip Calculations
Quickly calculate tip percentages for restaurant bills and split costs among groups.
Price Comparisons
Find the percentage increase or decrease between original and sale prices.
Discount Analysis
Determine discount percentages and final prices when shopping online or in-store.
Tax Rate Computing
Calculate sales tax rates and tax amounts for business and personal finances.
Grade Calculations
Figure out what percentage one number is of another for grades and statistics.