Percentage Calculator
Calculate X% of Y, what percent X is of Y, and percentage change.
X% of Y
X is what % of Y
Percentage Change
About Percentage Calculations
This calculator performs common percentage operations and runs entirely in your browser.
About this Percentage Calculator
Calculate percentages in the most common ways: find X% of a number Y, find what percent X is of Y, or compute percentage change between two values. Used daily for discounts, tips, grades, tax, and growth rates. Enter your numbers and get an instant, accurate result with no signup or server uploads. All calculations run in your browser, so your figures stay private. Ideal for students, shoppers, analysts, and anyone who needs quick percentage answers without opening a spreadsheet.
Key Features
Calculate X% of Y (e.g., 20% of 80 = 16)
Find what percent X is of Y (e.g., 16 is 20% of 80)
Compute percentage change between two values (e.g., old vs new)
Instant results as you enter values
Clear labels and optional copy of the result
Runs in your browser; no data sent to servers
How to Use
Choose the type of calculation: "X% of Y", "X is what % of Y", or "Percent change"
Enter the known values in the input fields
View the result; the tool updates as you type
Use the result for your discount, tip, grade, or report
Popular Use Cases
Discounts: find the sale price (e.g., 25% off) or the amount saved
Tips: compute 15% or 20% of a bill
Grades: see what percent a score is of the total, or find a weighted percentage
Growth rates: calculate percent increase or decrease between two numbers
Tips & Best Practices
Percent change = (new − old) / old × 100. Positive means increase, negative means decrease.
For "X% of Y", think: multiply Y by X/100. Example: 20% of 80 = 80 × 0.20 = 16.
To find "X is what % of Y", divide X by Y and multiply by 100.
Frequently Asked Questions
How do I find percent change?
Percent change = (new − old) / old × 100. Enter the old and new values in this tool and it will compute the percentage change for you.
What is X% of Y?
Multiply Y by X/100. Example: 20% of 80 = 80 × 0.20 = 16. Use the "X% of Y" mode and enter X and Y.
Can I use this for tips or tax?
Yes. For a tip, use "X% of Y" with X = tip percent (e.g., 15 or 20) and Y = bill amount. Same idea for tax.
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