A general percentage calculator for common percent questions
This percentage calculator handles the three percent formulas people search for most often: percentage change, percentage difference, and percentage error. Choose the calculation type, enter two values, and the calculator returns both the numeric result and the calculation steps.
percentage = ratio x 100
Which percentage formula should I use?
Use percentage change when one value is the starting value and the other is the new value. Use percentage difference when you are comparing two values without treating either one as the original. Use percentage error when you are comparing an observed value against a known true or expected value.
Common examples
If a price moves from 80 to 100, percentage change tells you the increase from the original price. If two measurements are 80 and 100 and neither one is the baseline, percentage difference compares them against their average. If an experiment measured 80 when the accepted value is 100, percentage error measures the miss against the accepted value.