Percent change

[Guest]

how do I calculate the percent change of several numbers? or is there a way to combine two percent changes or get an avg of the two?
ex. new values: 18 and 25 old values: 37 and 35

I was told the answer is a total reduction of 59.19% but can't seem to get that answer

[HallsofIvy]

I am afraid that is a very confusingly worded problem. The "old values" were 37 and 35 and the "new values" are 18 and 25. The old and new values of what? Do you mean that something went from 37 to 18 and something else went from 35 to 25? If so 18- 37= -15 and that is -15/37= -.405 or -40.5% of 37. 25- 35= -10 and that is -10/35= -0.286 or- 28.6% of 35.

Since these are of different bases there is no standard way to combine those percentages. IF you are concerned with their sums, you could say that 37+ 35= 72 and their total went down to 18+ 25= 43. 43- 72= -29 and -29/72= -.402 which is -40.2% of 72.

If you are interested in averages, the average of 37 and 35 is 36 while the average of 18 and 25 is 21.5. 21.5- 36= -14.5 and -14.5/36= -.402 or -40.2% again. But that is NOT CLOSE to (-40.5- 28.6)/2= 34.55%, the average of the original percentages.

[ollielemay]

Okay, that makes sense. Thanks for the answers.
wobble man

[TamaraParker]

It's very helpful, thanks!

[Guest]

Try to carry out all the calculations in Excel, it is easier to build reports there, also by api you can configure yourself any percentage calculator online or manually use it, I use it http://www.pctcalculator.com/

[stineylee]

To calculate the percent change between two numbers, you can use the following formula:

Percent Change = ((New Value - Old Value) / Old Value) * 100

Let's calculate the percent change for your example:

For the first set of values:
New Value = 18
Old Value = 37

Percent Change = ((18 - 37) / 37) * 100
Percent Change = (-19 / 37) * 100
Percent Change ≈ -51.35%

For the second set of values:
New Value = 25
Old Value = 35

Percent Change = ((25 - 35) / 35) * 100
Percent Change = (-10 / 35) * 100
Percent Change ≈ -28.57%

To combine two percent changes or calculate their average, you have a few options:

Additive Method: If you want to combine two percent changes, you can add them together. For example, if you have percent change A and percent change B, the combined percent change would be A + B.

Weighted Average: If you want to calculate the average of two percent changes, you can use a weighted average approach. Assign weights to each percent change based on their importance or significance. Then, multiply each percent change by its corresponding weight, add them together, and divide by the sum of the weights.

For example, if you have percent change A with a weight of 2 and percent change B with a weight of 1, the weighted average percent change would be ((A * 2) + (B * 1)) / (2 + 1).

Remember to adjust the signs (+ or -) of the percent changes based on whether they represent increases or decreases.

Using the above methods, you can combine or calculate the average of percent changes based on your specific needs and requirements.