Does excel really lack this function?

I canīt believe that I canīt Google the answer to this simple problem:

Below are 7 dates with index prices (SP500)

Jan 05, 2006 1273.48 0.00%
Jan 06, 2006 1285.45 0.94%
Jan 09, 2006 1290.15 0.37%
Jan 10, 2006 1289.69 -0.04%
Jan 11, 2006 1294.18 0.35%
Jan 12, 2006 1286.06 -0.63%
Jan 13, 2006 1287.61 0.12%


What I need to calculate is the average return for these three dates in percentages.

I obviously am working on historical data of several decades, but I need to find the historical growth rate of a certain period, and to make it simple I chose one week.

Could someone please show me how to calculate the average return for the first 3 dates. It would need to work so that once I copy the formula down to lower cells, it will always calculate the average of the 3 previous days.

So on Jan 9th we get average return for Jan 5th 6th and 9th, and on Jan 10th we get average return for Jan 6th 9th and 10th and so on.

I need to calculate average historical returns over a ten week period of time for the last 3 decades for any given date.

Hope someone smarter can help.

Mr Shorty:

I'll give you an example.

If a stock price is 100$ today, 110$ tomorrow and 120$ the day after, itīs easy to see that the price went up 20% in 3 days.
By average growth, I mean I need a formula to calculate the growth in 3 days in percentages. Thats why the first answer to this thread doesnt work. It gives the average price of the share in currency (i.e. if a shars is up from 100$ to 110$ in two days average price in that time period is 105$)

Question is, how do I get the growth percentage.

So you need the percentage difference between the 1st value and the 3rd value ?

Try

=B3/B1-1

Originally Posted by Jonmo1

So you need the percentage difference between the 1st value and the 3rd value ?

Try

=B3/B1-1

This is how you would get the % difference between the figures.

The -1 removes the 100% element, leaving you with the apportioned % increase.

Thanks, I thought it was much more complicated but the answer was too simple for me to see

One question: Do you know a way to change periods into commas? I have 2400 entries all in this form 1.1 and excel needs it to be 1,1 to recognize it. Thanks very much for all the help so far!