Percentage Calculator

Instantly calculate percentages: X is what % of Y? What is X% of Y? Fast, private, and works entirely in your browser.

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What is a Percentage?

A percentage is a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign, “%”. For example, 45% (read as “forty-five percent”) is equal to 45/100, or 0.45.

Percentages are widely used in daily life to calculate discounts, tips in restaurants, interest rates, tax calculations, and interpreting statistics. They provide a standard way of expressing proportions, making it easier to compare different quantities.

Common Percentage Formulas

1. What is X% of Y?

Result = (X / 100) × Y

Example: 20% of 150 = (20 / 100) × 150 = 30

2. X is what percent of Y?

Result = (X / Y) × 100

Example: 45 is what percent of 90? = (45 / 90) × 100 = 50%

3. Percentage Change (Increase/Decrease)

Result = ((New Value - Old Value) / |Old Value|) × 100

Example: Price goes from $40 to $50. Change = ((50 - 40) / 40) × 100 = +25% (Increase)

Real-World Examples

Tip Calculation

If your restaurant bill is $85 and you want to leave a 15% tip:
Tip = 15% of $85 = $12.75.
Total to pay = $85 + $12.75 = $97.75.

Discount Calculation

A jacket originally costs $120 and is on a 25% discount.
Discount = 25% of $120 = $30.
Final Price = $120 - $30 = $90.

People Also Ask

How do I calculate percentage increase?
Percentage increase = ((New Value − Old Value) / Old Value) × 100. For example, if a price goes from ₹200 to ₹250, the increase is ((250 − 200) / 200) × 100 = 25%.
How do I find what percent one number is of another?
To find what percent X is of Y, use the formula: (X / Y) × 100. For example, 45 is (45/200) × 100 = 22.5% of 200.
What is the difference between percentage and percentile?
Percentage is a fraction of 100 (e.g., 85% means 85 out of 100). Percentile indicates the position of a value relative to a dataset — the 90th percentile means you scored better than 90% of all values. They measure different things.