Percent Difference

Use when comparing two values where neither value is considered a start value or a reference value.



One Value Another Value Percent Difference
                     %


Note: There is no standard equation for percent difference for all circumstances. The equation used here divides the difference between the two values by the average of the two values (see equation below). Some cases may require you to divide by the minimum of the two values or the maximum of the two values, etc. Please check that the equation used here fits your circumstance. Also see *** note at the bottom of this page.


Equation used:
Percent Difference  =  
abs(One Value - Another Value)abs((One Value + Another Value)/2))
   x 100%
(where abs = absolute value)

(Enter values into the blue boxes. Answer will appear in the black box.)
Answers are rounded to 7 decimal places.



Examples

Example 1:
In one cup there are 5 marbles.
In another cup there are 8 marbles.
What is the percent difference in the number of marbles?

One Value = 5
Another Value = 8
Percent Difference = 46.15%

Click to show this example in the calculator above.


Example 2:
Group A has 330 people.
Group B has 225 people.
What is the percent difference in the number of people?

One Value = 330
Another Value = 225
Percent Difference = 37.8%

Click to show this example in the calculator above.


Example 3:
Profit for one company totaled $25,000.00
Profit for another company totaled $100,000.00
What is the percent difference in profit?

One Value = 25000.00
Another Value = 100000.00
Percent Difference = 120%

Click to show this example in the calculator above.




*** Note: When there is a large difference between the two values being compared, the percent difference equation shown at the top of the page may not provide an acceptable answer for your circumstance. For example, if one value=1 and the other value=10000, the percent difference is 200 percent. But, if the second value instead of being 10000 is 100000000 the percent difference is still 200 percent. Using this equation, the maximum percent difference will never be higher than 200% (if both numbers have the same sign, both numbers are positive or both numbers are negative.) This maximum is due to: a large number minus a small number is still a large number and the average of a large number and a small number is approximately one half of the large number. Thus the equation is taking a large number and dividing it by one half of itself which equals approximately 2. Then to complete the equation, 2 x 100% = 200%