Percentage change measures how much a value has increased or decreased relative to its original amount. It is one of the most common calculations in finance, business, science, and everyday life. Whether tracking stock prices, comparing sales figures, or monitoring weight loss, percentage change puts differences into perspective.

The formula is: Percentage Change = (New Value - Original Value) / |Original Value| x 100. A positive result indicates an increase, while a negative result indicates a decrease. The absolute change is simply the difference between the two values without considering proportion.

For example, if a product's price rises from $250 to $325, the absolute change is $75 and the percentage change is +30%. The multiplier of 1.30x means the new value is 1.3 times the original. Note that percentage changes are not symmetric: a 50% increase followed by a 50% decrease does not return to the original value. Understanding this asymmetry is important for accurate financial analysis.