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🔢 Percentage Calculator

Every Percentage
Calculation

Tips, discounts, tax, percentage change, what % is X of Y — seven types of calculations with step-by-step explanations.

🎯

What is X% of Y?

Percentage
%
Of this number
$
Result17
🔍

X is what % of Y?

X (the part)
$
Y (the whole)
$
Result12.5%
📈

Percentage Change

From (original value)
$
To (new value)
$
Percentage Change+25%
🍽️

Tip Calculator

Bill Amount
$
Tip Percentage
%
Split Between
people
Tip Amount$0
Total Bill$0
Per person: $0
🏷️

Discount Calculator

Original Price
$
Discount
% off
Sale Price$0
You Save$0
🧾

Add Sales Tax

Pre-tax Price
$
Tax Rate
%
Tax Amount$0
Total Price$0
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Percentage Difference

Value A
Value B
Percentage Difference40%
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Reverse Percentage

"If X is Y% of a number, what is the original number?"

Known Value
$
Is this % of the original
%
Original Number$120

How Percentage Calculations Work

A percentage is simply a fraction out of 100. "25%" means 25 per 100, or 0.25 as a decimal. To find X% of Y, multiply Y by X/100. For example, 20% of $85 = 85 × 0.20 = $17.

Percentage Change vs. Percentage Difference

Percentage change measures how much a value increased or decreased from a starting point. Percentage difference compares two values without a starting point — it uses the average of both as the base.

How to Calculate a Tip Quickly

To calculate a 20% tip mentally: move the decimal point one place left to get 10%, then double it. On a $65 bill: 10% = $6.50, doubled = $13. Done in seconds.

Sales Tax Explained

Sales tax varies by US state from 0% (Oregon, Montana, New Hampshire) to over 10% in some cities. To calculate the tax-inclusive price: multiply the pre-tax price by (1 + tax rate). A $100 item with 8.5% tax = $108.50.