How It Works
Percent change measures how much a value has increased or decreased relative to its original amount. It shows the relative difference between two numbers as a percent, making comparisons easier across different scales.
To compute the percent change from an original value to a new value, subtract the original from the new value, divide the result by the original value, and multiply by 100.
Percent change = ((New − Original) ÷ Original) × 100
For example, if a price moves from 80 to 100, the percent change is ((100 − 80) ÷ 80) × 100 = 25%. A negative result indicates a decrease. If the original value is zero, the percent change is undefined because division by zero is not valid.
Interpretation
Positive percentages indicate increases (growth), negative percentages indicate decreases (loss). Percent change is widely used in finance, analytics, and reporting to convey relative movement over time or between states.
Accuracy and Rounding
When precision matters, keep extra decimal places. The toggle above rounds to two decimals for convenience. Tools should always handle decimal inputs and detect division-by-zero conditions rather than returning misleading numbers.