How It Works
The result after adding X percent to a number is:
Result = Value × (1 + X ÷ 100)
For example, 100 + 25% = 100 × (1 + 25 ÷ 100) = 125. If X is negative the value decreases.
When the base value or percent are decimals the same formula applies. If the base value is not a finite number the calculator will prompt for valid input.