Percentage Calculator

100% Free · Client-Side

Instantly calculate percentages. Find discounts, tax, margins, percentage increase/decrease, and reverse percentages with our free online calculator.

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Free Online Percentage Calculator

The Free Online Percentage Calculator is a simple, fast tool to solve everyday math problems. Whether you need to figure out a discount, calculate sales tax, find a percentage increase or decrease, or simply figure out what X percent of Y is, this tool gives you instant answers as you type.

How to calculate percentages

Calculating percentages doesn't have to be confusing. Here are the basic formulas used by our tool:

What is X% of Y? Formula: (X / 100) * Y. Example: 20% of 150 = (20 / 100) * 150 = 30.
X is what percent of Y? Formula: (X / Y) * 100. Example: 30 is what percent of 150? = (30 / 150) * 100 = 20%.
Percentage Change: Formula: ((New - Old) / Old) * 100. Example: Increase from 100 to 120 = ((120 - 100) / 100) * 100 = 20%.

Frequently Asked Questions

How do I calculate a discount?

To calculate a discount, use the 'Subtract Percentage' calculator. Enter the original price as the first number (X) and the discount percentage as the second number (Y). For example, 100 minus 20%.

How do I calculate sales tax or a tip?

To calculate tax or a tip and get the total amount, use the 'Add Percentage' calculator. Enter the pre-tax amount (X) and the tax/tip percentage (Y). If you just want to know how much the tax/tip itself is, use the 'What is X% of Y' calculator.

Is my data stored anywhere?

No! This calculator runs entirely in your web browser. No data is sent to our servers, and everything is calculated instantly on your device.