Calculate Percentage Decrease

You can use the percentage decrease calculator below to work out your figures if you are looking for a quick answer, below the calculator you will also find the workings behind the answer and the percentage decrease formula.  If you want to reduce a number by a percentage then you can use the percentage off calculator here.

Percentage Decrease Calculator

Percentage Decrease: 20%

How to work out percentage decrease

Here is the method for working out what percentage a decrease in an amount represents. A is the initial value and B is the decreased value - which means you can calculate C as the change:

  1. Firstly calculate the decrease (C): A − B = C
  2. Now divide the decrease (C) by the original value (A): C ÷ A = D
  3. Finally multiply this amount by 100: D × 100 = The Percentage Decrease

With the figures in the calc above you would do the following:
100 - 80 = 20 Then: 20 / 100 = 0.2 Then: 0.2 x 100 = 20 - showing a 20% decrease in the amount.

Percentage Decrease Formula

To tidy up the example above and show it as a formula we can represent the Percentage Decrease as P, the initial amount as A and the decreased amount as B.

P = ((A − B) ÷ A) × 100