Percent error is a measure of how far off or how precise/accurate your answer is compared to the actual answer.
The formula for percent of error is very similar to the formula for percent of change. One key difference between percent error and percent change is that percent error can NOT be negative, while percent change can be negative because it shows us that the value decreased. Percent error is just asking how far away was the estimate from the actual value. It does not matter whether it was more or less than the actual value.
Percent change is a way of describing how much something has changed over a period of time from its original value. The basic formula for finding the percent change is to find the difference between the original and the new values and to divide that difference by the original value.
It is most helpful to see how an item has increased or decreased.