Percentage Calculator

Calculate percentages, percentage change, difference, increase, and decrease instantly.

Percentage Calculator tool

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Example

Input: What is 15% of 80? (mode: X% of Y, X = 15, Y = 80)

Result: Result 12 (15% of 80 = 12, as decimal 0.15)

X% of Y = (X / 100) x Y, so (15 / 100) x 80 = 0.15 x 80 = 12.

Why a Rise and a Fall Are Not Equal

Increase from 100Change needed to get back
+10% (100 to 110)-9.09% (110 to 100)
+20% (100 to 120)-16.67% (120 to 100)
+25% (100 to 125)-20% (125 to 100)
+50% (100 to 150)-33.33% (150 to 100)
+100% (100 to 200)-50% (200 to 100)
+200% (100 to 300)-66.67% (300 to 100)

Percentage change from this calculator, rounded to 2 decimals.

  1. Select the calculation mode: X% of Y, X is what % of Y, percentage change, percentage difference, or increase/decrease.
  2. Enter the required numbers in the input fields for your chosen calculation mode.
  3. View the calculated percentage result instantly as you type.
  4. Switch between modes to perform different percentage operations on the same values.
  5. Click the copy button to copy any result to your clipboard.

How to Work Out Percentages

To find X% of Y, multiply Y by X and divide by 100, so 15% of 80 is 12. This calculator does that and four other everyday percentage jobs. It finds what percent one number is of another, the percent change between two values, the percent difference, and a value after a percent increase or decrease.

Each question people ask maps to one mode. "I scored 42 out of 50" is X is what % of Y, which gives 84%. "My rent went from 1,200 to 1,290" is percentage change, which gives a 7.5% increase. "What is 20% off 60?" is the increase or decrease mode, which shows 48 after the cut. "Two quotes of 180 and 220" is percentage difference, which compares them without picking a starting point and gives 20%.

The trickiest part is that a rise and a fall are not mirror images. Add 50% to 100 and you get 150. Take 50% off 150 and you get 75, not 100. To undo a 50% rise you need a 33.33% cut, as the table on this page shows. This is why a price that rises and then falls by the same percent ends up lower.

Also keep percent and percentage points apart. If an interest rate moves from 4% to 5%, it rose by 1 percentage point, but by 25 percent. For shopping, the Discount Calculator adds sale-specific details. For business pricing, the Markup vs Margin Calculator explains why a 50% markup is only a 33% margin.

Formula / How It Works

X% of Y = (X / 100) x Y | % Change = ((New - Old) / Old) x 100 | % Difference = (|A - B| / ((A + B) / 2)) x 100

Frequently Asked Questions

Divide the part by the whole and multiply by 100. If you got 42 out of 50, that is 42 / 50 x 100 = 84%. In the calculator, pick X is what % of Y, enter the part as Value A and the whole as Value B. It also shows the answer as a decimal, 0.84.
Percentage change has a direction. It measures a move from an old value to a new one, using the old value as the base. Percentage difference has no start or end. It compares two values using their average as the base. So 180 and 220 are 20% apart, while going from 180 to 220 is a 22.22% increase.
Multiply the number by 1 plus the percent as a decimal. A 20% rise on 150 is 150 x 1.2 = 180. To take 20% off, multiply by 0.8 instead, which gives 120. The increase or decrease mode shows both results at once, plus the size of the change, which is 30 here.
Because each percent is taken from a different base. A 50% rise on 100 adds 50, giving 150. A 50% drop on 150 removes 75, leaving 75. To get back to 100 from 150 you only need a 33.33% drop. The larger the swing, the bigger this gap becomes.
A percentage point is the plain gap between two percentages. A percent change is that gap measured against the starting value. If a rate goes from 4% to 5%, it rose by 1 percentage point, but that is a 25% increase. News reports and loan offers often mix the two up.

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