How this calculation works
Choosing the average as the denominator makes the calculation symmetric. To measure growth relative to a baseline, use percentage change.
100 × |a − b| / ((a + b)/2)A worked example
80 and 120 differ by 40, which is 40% of their average of 100.
Good to know
Use positive values in the same units. Swapping them gives the same result.
Reference: OpenStax Prealgebra (opens in a new tab) ↗
Read the result
Compare two positive measurements using their average as the reference.
The primary result is labeled “Percentage difference (%)”. Keep the input definitions in view when comparing this result with another method.
Try a related calculation
Use positive values in the same units. Swapping them gives the same result.
For a related exercise, try the fraction calculator.
A few questions, answered
How can I check the default inputs by hand?
80 and 120 differ by 40, which is 40% of their average of 100.
Which rule does this calculator apply?
100 × |a − b| / ((a + b)/2)