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Calculate a Percentage of Something

Updated · Standard formula, shown below

p% of the number 36.00
The number minus p%
204.00
Result
The number plus p%
276.00
Result
Percentage
15 %
You entered

This calculator finds a percentage of a number, such as 15% of 240. Enter the percentage and the number, and you get the part, what remains after taking it away, and the number increased by that percentage.

Formula

Part = p ÷ 100 × x. Decrease: x − part = x × (1 − p ÷ 100). Increase: x + part = x × (1 + p ÷ 100).

  • p: the percentage
  • x: the whole amount (any unit)

Worked Example

15% of 240.

  1. 15 ÷ 100 = 0.15; 0.15 × 240 = 36.00
  2. 240 − 36 = 204.00
  3. 240 + 36 = 276.00

Limits and common mistakes

  • A rise of p% followed by a fall of p% does not return to the start: 240 + 15% = 276, and 276 − 15% = 234.60.
  • “Percent of” and “percentage points” differ: going from 10% to 15% is 5 points but a 50% rise.
  • Enter 15 for 15%, not 0.15.
  • To find what percent one number is of another, divide and multiply by 100: 36 ÷ 240 × 100 = 15%.
  • A discount of 15% means you pay the “minus” value (204.00); a 15% tip or surcharge is the “plus” value (276.00).
Formula used
in p | Percentage | % | 15
in x | Of the number | - | 240
out part | p% of the number | - | p / 100 * x | 2
out rest | The number minus p% | - | x - part | 2
out up | The number plus p% | - | x + part | 2

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.