# How do you calculate monthly growth rate from annual growth rate in Excel?

JjujuBoard RegularJoinedMar 13, 2008Messages172Jan 4, 2013#1I am comparing the average monthly growth rate of a couple of different 12 month series values. To do that, for each ser

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#### juju

##### Board RegularJoinedMar 13, 2008Messages172

- Jan 4, 2013
- #1I am comparing the average monthly growth rate of a couple of different 12 month series values. To do that, for each series, I calculated the month over month growth ((Current Month - Previous Month) / Previous Month ) * 100, then averaged it all out over the 12 months. However, is this a fair comparison of the average of each series? I have one series which has relatively small monthly values, so any small month over month change registers a huge monthly % growth value, which of course impacts its 12 month average, making it look like its growing faster than the other series.

What is the best way to compare the overall average growth rate for a couple of different series when one has big outliers which skews it values. In absolute terms, the one with the small values contributes very little to the overall picture. Thx.

#### alansidman

##### Well-known MemberJoinedFeb 26, 2007Messages6,835Office Version

- 365Platform
- Windows

- Jan 5, 2013
- #2How about using a CAGR

Here is a UDF that you can copy and paste

Code:Function CAGR(First, Last, Periods) CAGR = ((Last / First) ^ (1 / Periods)) - 1 End Function

Compound annual growth rate - Wikipedia, the free encyclopediaLast edited: Jan 5, 2013