Percentage Difference Calculator
Calculate the percentage difference between two numbers. Unlike percentage increase or decrease, percentage difference is symmetric — it does not matter which number came first. Enter your two values below.
Percentage increase and{' '} decrease are directional: one value is the original and the other is the new value, so the result depends on which is which. Percentage{' '} difference has no direction — it uses the average of the two numbers as the reference, so swapping them gives the same answer. Use it when you are simply comparing two values, not measuring change over time.
Comparing 40 and 60: the difference is{' '} {formatNumber(EXAMPLE.diff, 0)} {' '} and the average is {formatNumber(EXAMPLE.avg, 0)}, so:
Percentage difference vs increase and decrease
Worked example
Frequently asked questions
What is the percentage difference between two numbers?
Percentage difference compares two values without treating either as the starting point. You take the absolute difference, divide by the average of the two values, then multiply by 100. For 40 and 60 that is |40 − 60| ÷ ((40 + 60) ÷ 2) × 100 = 40%.
How is percentage difference different from percentage increase or decrease?
Percentage increase and decrease are directional — one value is the original and the other is new. Percentage difference is symmetric: swapping the two numbers gives the same result, because it uses the average as the reference rather than a single starting value.
What is the percentage difference formula?
Percentage difference = |A − B| ÷ ((A + B) ÷ 2) × 100. The average of the two numbers is the denominator, which is why the result is the same whichever number you call A or B.
Why can both numbers not be zero?
If both numbers are zero their average is zero, and dividing by zero is undefined. Enter at least one non-zero number to get a valid percentage difference.
Related converters and pages
How our calculations are produced · Conversion guides · About EasyConvertCalc