Free Percentage Calculator — Find X% of Any Number Online
Calculate percentages instantly — find X% of Y, what percent X is of Y, or the percentage change between two values.
Result
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How it works
Choose your mode
Select from three calculation modes: X% of Y, X is what % of Y, or % change.
Enter your values
Type the numbers into the input fields — results update as you type.
Read the result
Your answer appears instantly with the formula shown for reference.
Stay private
All calculations run in your browser. Nothing is sent to any server.
Common use cases
Shopping discounts
Quickly find the sale price when a store offers 20% or 30% off an item.
Tax calculations
Calculate VAT, GST, or sales tax on any purchase amount instantly.
Grade & score analysis
Find out what percentage you scored on a test or how much your grade improved.
Business metrics
Calculate profit margins, growth rates, and performance percentage changes.
Frequently asked questions
How do I calculate X% of a number?
Use mode 1: enter X (the percent) and Y (the number). The result is (X/100) × Y. For example, 15% of 200 = 30.
How do I find what percentage X is of Y?
Use mode 2: enter X and Y. The result is (X/Y) × 100. For example, 30 is 15% of 200.
How do I calculate percentage change?
Use mode 3: enter the original value and the new value. The result is ((new − original) / original) × 100. A positive result means increase, negative means decrease.
Is this calculator free?
Yes, completely free with no account or signup required.
Does it work on mobile?
Yes — the calculator is fully responsive and works on phones and tablets.
Are my inputs stored anywhere?
No. All calculations happen in your browser tab using JavaScript. Nothing is transmitted to any server.