Percent Change Calculator
Find the percentage increase or decrease between two values along with the absolute difference.
Increase
- 1
Absolute difference
V2 − V1 = 150 − 120 = 30 - 2
Divide by |V1|
30 ÷ 120 = 0.25Dividing by the absolute value of V1 keeps the sign tied to the direction of change. - 3
Percent change
(30 ÷ 120) × 100 = 25
How does this calculator work?
Percent change is (new − old) divided by the absolute value of the old number, times 100. A positive result is an increase and a negative result is a decrease. The calculator also shows the absolute difference. It returns nothing when the old value is zero, since dividing by zero is undefined.
Formula
How this is calculated
Enter the old value (V1) and the new value (V2). The percent change measures how much V2 has grown or shrunk relative to the original value: percent change = (V2 − V1) / |V1| × 100. Dividing by the absolute value of V1 keeps the sign of the change tied to the direction of movement even when the starting value is negative.
A positive result means an increase, a negative result means a decrease, and zero means the value is unchanged. The absolute difference (V2 − V1) is reported separately in the same units as your inputs, which is useful when the raw size of the change matters as much as the percentage.
The percentage is undefined when the old value is zero, because dividing by zero has no meaningful result — in that case no output is shown. The range meter clamps very large percentages to the −100% to +100% scale for display, but the exact figure is always given in the headline result.
Frequently asked questions
Percent change compares a new value against a specific original (old) value, so order matters. Percent difference compares two values against their average and is direction-neutral.
Percent change divides by the old value. If the old value is zero, the division is undefined, so any increase from zero cannot be expressed as a percentage.
A decrease produces a negative percent change. For example, going from 150 to 120 is (120 − 150) / 150 × 100 = −20%.
Also known as
TG we-Calculate Editorial Team. (2026). Percent Change Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/percent-change-calculator
TG we-Calculate Editorial Team. "Percent Change Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/percent-change-calculator.
TG we-Calculate Editorial Team, "Percent Change Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/percent-change-calculator
@misc{wecalculate_percent_change_calculator, title = {Percent Change Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/percent-change-calculator}}, year = {2026}, note = {TG we-Calculate} }
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