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Percentage Calculator

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A percentage is just a fraction of 100 — this tool covers the three calculations people search for most: finding a percentage of a number, finding what percentage one number is of another, and finding the percentage change between two numbers. Pick a mode below and the result updates as you type.

Percentage Calculator

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15% of 200 is
30
Updates instantly — nothing is sent to a server.

How to calculate a percentage

All three calculations above come from the same idea: a percentage is a number out of 100. Once you can convert between a percentage and a decimal (divide by 100), the rest is ordinary multiplication or division.

Formula: X% of Y

result = (X ÷ 100) × Y
Example

What is 15% of 200?
(15 ÷ 100) × 200 = 0.15 × 200 = 30

Formula: X is what percent of Y

result = (X ÷ Y) × 100
Example

30 is what percent of 200?
(30 ÷ 200) × 100 = 0.15 × 100 = 15%

Formula: Percentage change

change = ((new − old) ÷ |old|) × 100
Example

A price moves from 200 to 250.
((250 − 200) ÷ 200) × 100 = (50 ÷ 200) × 100 = +25%

Step-by-step guide

  1. Choose your calculation type. Are you looking for a portion of a number, a percentage relationship between two numbers, or how much something changed?
  2. Enter your two numbers. The calculator updates the result as you type — there's no submit button.
  3. Read the result. For percentage change, a positive number means an increase and a negative number means a decrease.
  4. Copy or share if needed. Use "Copy result" to paste the figure elsewhere, or use the share icons above to send the page link.

Common mistakes

Forgetting to use the absolute value of the starting number in percentage-change calculations, which can flip the sign of the answer when the starting value is negative.
Confusing "percentage of" with "percentage change" — a value going from 50 to 75 is a 50% increase, not "75%".

Frequently asked questions

What's the difference between percentage and percentage points?

A percentage point is the simple difference between two percentages (e.g. going from 40% to 45% is "5 percentage points"). A percentage change describes that same move relative to the starting value (5 ÷ 40 = a 12.5% increase). They're easy to mix up in news headlines.

Can a percentage be more than 100%?

Yes. Anything over 100% simply means the part is larger than the whole you're comparing it to — common when describing growth, such as sales that more than doubled (a 150% increase).

How do I reverse a percentage increase?

Divide the new value by (1 + the percentage as a decimal). For example, to find the original price before a 25% increase to $250: 250 ÷ 1.25 = $200.

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