Percentage Decrease Calculator

Find how much a value dropped in percent, or reduce any number by a percentage. The percentage decrease calculator shows the difference and every step.

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Calculation

Percentage decrease
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How to use the Percentage Decrease Calculator

  1. Choose a tab: Decrease from A to B to measure a drop, or Decrease a value by P% to reduce a number.
  2. Enter the original value and the new value, or the value and the percentage.
  3. Press Calculate. You get the percentage decrease and the difference, or the reduced value and the amount taken off.

How it works

Decrease from A to B:

decrease % = (A − B) ÷ |A| × 100

Decrease a value by P%:

new value = V × (1 − P ÷ 100)
  • A: the original value
  • B: the new value
  • V: the value to reduce
  • P: the percentage to take off

Examples

  • From 80 to 60 is a 25% decrease (−20).
  • 250 decreased by 40% is 150 (−100).

Why a decrease and an equal increase don't cancel out

Take 80 and cut it by 25%: you get 60. Now raise 60 by 25%: you get 75, not 80. The increase is worked out on the smaller number, so 25% of 60 is only 15.

To get back to where you started after a 25% drop, you need a 33.3% rise. This catches people out with prices, salaries, and investment returns, where a loss needs a bigger gain to recover.

Limitations

  • An original value of 0 gives an undefined-result message.
  • If the new value is higher than the original, the result is negative. Use the percentage increase calculator for growth.
  • Reducing a value by more than 100% gives a negative result, with a note.

Frequently asked questions

How do I calculate a percentage decrease?

Subtract the new value from the old value, divide by the old value, and multiply by 100.

Why doesn't a 25% drop followed by a 25% rise get me back to the start?

The rise is calculated on the smaller number. 80 drops to 60, and 25% of 60 is only 15, so you end at 75.

Can a decrease be more than 100%?

Only if the value goes below zero, for example a profit turning into a loss. For prices and quantities, 100% is the maximum.

Often used together with the Percentage Decrease Calculator.