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Percentage Calculator

Solve three everyday percentage problems in seconds: what is X% of Y, X is what % of Y, and percentage increase/decrease.

100% free No sign-up Private · runs in your browser

How to use the free online percentage calculator

Pick the type of percentage problem.
Enter the two/three numbers involved.
Get the result plus the formula that produced it.
Copy the answer if needed.

About this tool

Solve everyday percentage problems: what is X% of Y, X is what percent of Y, and percentage increase or decrease between two numbers. Perfect for discounts, tips, growth rates, grade calculations and shopping math. Enter two numbers, get the answer instantly — with the formula shown so you can learn as you go.

Key features

3 problem types
Step-by-step working
Increase / decrease
Handles decimals

Privacy first: every calculation and generation runs 100% locally in your web browser using the Web Crypto API. Your input never touches a server — nothing is stored, logged or sold.

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Frequently asked questions

Multiply the number by the percentage divided by 100. Example: 15% of 200 = 200 × 15/100 = 30. Our calculator does this instantly.

Divide X by Y and multiply by 100. Example: 25 is what percent of 200? → 25/200 × 100 = 12.5%.

Divide the change by the original value and multiply by 100. From 80 to 100 is a 25% increase: (100-80)/80 × 100 = 25%.