Percentage Increase / Decrease Calculator
Add a percentage to a value or take a percentage off it, and see the new amount.
Percentage Increase / Decrease
Add a percentage to a value or take a percentage off it.
by%
Increase 100 by 20%
120
How it works
Enter the starting value, a percentage, and whether to increase or decrease by it.
The value is multiplied by (1 + percentage ÷ 100) to increase, or (1 − percentage ÷ 100) to decrease.
To find the percentage between two values you already know, use Percentage Change instead.
Formula
increase: result = value × (1 + percentage ÷ 100)
decrease: result = value × (1 − percentage ÷ 100)
Worked example: Increasing 200 by 15% gives 230
More examples and edge cases
- Decreasing 200 by 15% gives 170
- Increasing 100 by 20% gives 120, but decreasing that by 20% gives 96, not 100 — the second percentage is taken of the larger number