Percentage Change Calculator
Calculate the percentage increase or decrease between an original value and a new value.
Runs locally in your browser
Your inputs are processed locally in your browser and are not uploaded or stored by us.
Calculate the percentage change between an original value and a new value. See whether the value increased, decreased, or stayed the same, along with the absolute difference.
How to use the Percentage Change Calculator
- Enter the original value.
- Enter the new value.
- Select Calculate.
- The calculator shows the percentage change, direction of change, and numerical difference.
Percentage change formula
Percentage change = ((New Value − Original Value) ÷ |Original Value|) × 100
For positive original values, this produces the standard percentage-change result. Using the absolute original value also gives the direction of change consistently when the original value is negative.
Percentage increase example
Original80
New100
(20 ÷ 80) × 100
Result: 25%
Notes
- Percentage decrease example: From 100 to 80. Difference is -20. (-20 ÷ 100) × 100 = -20%. The value decreased by 20%.
- What happens when the original value is zero? A percentage change cannot be calculated from an original value of zero because the percentage-change formula would require division by zero. For example, a change from 0 to 50 has an absolute difference of +50, but the percentage increase is undefined. Similarly, a change from 0 to -50 has a difference of -50, but the percentage decrease is undefined. If both values are zero, there is no change, so the calculator reports 0%.
- How are negative values handled? When the original value is negative, this calculator divides the difference by the absolute magnitude of the original value. For example, from -50 to -60: Difference is -10. (-10 ÷ 50) × 100 = -20%. The calculator therefore reports a 20% decrease. From -50 to 50: Difference is 100. (100 ÷ 50) × 100 = +200%. The calculator reports a 200% increase. Percentage changes involving negative values can be interpreted differently in some financial, scientific, or statistical contexts, so consider the meaning of the underlying values when using the result.
- Percentage Calculator vs Percentage Change Calculator: Use the Percentage Calculator when you want to calculate a percentage of a number, determine what percent one number is of another, or find a whole from a known percentage. Use the Percentage Change Calculator when you have an original value and a new value and want to measure how much the value increased or decreased relative to the original.