Percentage Decrease Calculator
Subtract a percentage from any number below. Here is the formula and a worked example so the maths is clear.
Decrease a number by a percent
Decreased value
170
Amount removed
30
How to decrease a number by a percentage
Multiply the number by the percentage and divide by 100 to get the reduction, then subtract it: new value = value × (1 − percent ÷ 100).
Example: decreasing 200 by 15% removes 30, giving 170.
Decrease vs increase are not symmetric
Decreasing then increasing by the same percentage does not return the original number. 200 decreased by 15% is 170; increasing 170 by 15% gives only 195.5, because the second percentage is taken from a smaller base.
Frequently asked questions
How do I subtract a percentage from a number?
Multiply the number by the percentage, divide by 100, then subtract that from the original. A 15% decrease on 200 is 200 − 30 = 170.