Skip to content
Math & Statisticspercentage

Percent of a Number Calculator

A percentage of a number, with the increase and decrease shown alongside. Finding a percentage and adding one are different questions and the page answers both.

Also called: what is x percent of y, percentage of a number.

Result
360

15% of 2,400 is 360. The rest, 2,040, is the other 85%.

The rest of the number
2,040
The remaining percentage
85%
What percent the result is of the original
15
The number increased by that percent
2,760
The number decreased by that percent
2,040
How this is calculated
Method and background

How this is calculated

A percentage is a hundredth, so fifteen percent is fifteen hundredths. The three answers people usually want are the part itself, the number with that percentage added, and the number with it taken off, so all three are here. Note that adding fifteen percent and then removing fifteen percent does not return the original, because the second percentage applies to a larger number.

result = percent / 100 * value
p
The percentage
V
The value

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

fifteen percent of 2400

What percent
15
Of this number
2,400

Result360

arithmetic identity

Open this example

a hundred percent is the whole number

What percent
100
Of this number
2,400

Result2,400

boundary

Open this example

zero percent is nothing

What percent
0
Of this number
2,400

Result0

degenerate case

Open this example

Method and limits

What it assumes

  • Ordinary arithmetic on real numbers.

What it deliberately does not model

  • Percentages of percentages compound and need care; this handles one step.

Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator

Frequently asked questions

Why does adding then removing 15% not get me back?
Because the removal applies to the increased number. 100 plus 15% is 115, and 15% off 115 is 97.75. To reverse an increase you divide rather than subtract.