Percentage Change Calculator
Calculate the percentage increase, decrease, or relative shift between an original number and a new number.
Run tool
This online percentage change calculator finds the relative shift between an original value and a new value. To calculate the change, the tool subtracts the original number from the new number to determine the signed difference. It then divides that difference by the absolute value of the original number and multiplies the outcome by one hundred. The calculator classifies the result as an increase, a decrease, or no change depending on whether the difference is positive, negative, or zero. You can enter positive or negative numbers for either field, including whole integers and decimal amounts. Because the calculation divides by the baseline magnitude, the original value cannot be zero. Both the numeric difference and the final percentage are rounded to ten decimal places using half-up rounding.
Instructions
- Enter the starting baseline number into the Original value field.
- Enter the ending comparison number into the New value field.
- Run the calculation to process the difference and rate of change.
- Review the resulting percentage, numeric difference, and direction indicator in the output area.
Examples
- Changing from an original value of 100 to a new value of 125 results in an increase of 25% with a difference of 25.
- Changing from an original value of 80 to a new value of 60 results in a decrease of 25% with a difference of -20.
- Starting at -50 and moving to -25 results in an increase of 50%, calculated as 25 divided by |-50| multiplied by 100.
FAQ
How is percentage change calculated?
The calculator subtracts the original value from the new value, divides that difference by the absolute value of the original number, and multiplies by 100.
Why cannot the original value be zero?
Calculating percentage change requires dividing by the absolute magnitude of the original number. Division by zero is mathematically undefined, so the original value cannot be zero.
Can I enter negative numbers?
Yes, both fields accept negative values. When the starting number is negative, the calculation uses its absolute value in the denominator.
How are fractional values rounded?
Both the numeric difference and the percentage value are rounded to ten decimal places using standard half-up rounding.