Inserting new column into chart data range and range keeps changing.

Okay this is driving me nuts, I can't believe this could be so complicated. heres my question. every month i create a report that graphs the last three months worth of reporting. i have a sheat that i put the info in. then i have to go and manually graph the last three months.

What I want to do is basically build a sheet for the three months for instance A1=March B1=Feb C1=JAN
Then every month I want to insert a new roa in front of A meaning the new row becomes A and the rest move down. (this part i got)
Problem is I want my graphs data range to stay the same. currently it changes with the previouse data.


PLEASE HELP>

Here's a way I did something similar. Where I add my new data in my calculations sheet I have a min formula for my dates, and I normalize my dates in a separate column so 8/22/14 becomes 8/1/14. Then I have an edate formula next to it that adds a month and same next to it covering all my date range. All my graphs refer to these values so every time I add new data all my graphs update automatically.

Give me a little time to create one.

see if something like the attached would be something you could use, to see how it would work, paste over the data in the "first sheet" with the data from the "new values" sheet to see how it would automatically update the chart.

For mine if you pasted new data anywhere in the graph the min formula will pull the minimum date wherever it appears in the data. You can do the same using max and use a negative with edate to get the most recent three months or the first three months and refer your graph data to that calculated area.

so here is a different version of what I was talking about. In this sample you add in your new values and the two tables will change to suit whether you add in data based on older dates (first three months) or newer dates (latest three months).

My latest version gives you the option to add new data and the graph will automatically update to the latest three months. All you have to do is apply the logic to your sheets.

you have confused things ,post #1 mentions rows
post #7 says columns
and your example in post #7 shows Aug-14 Sep-14 Oct-14
if you wanted to insert a new column you'd do it at the end
unless you mean
Oct-14 Sep-14 Aug-14 and you want to insert nov-14 before october

Thanks Martin for helping to define this more.
So, here is your sample back with formatting the way I would approach it.
First, I would insert your new data at the far left of the data set, so instead of it going form August to Sept to Oct etc i would have Aug at the far right end, to the left of it Sept, then Oct and keep inserting your new data in the first column you use (column C in your example).
then look at the calculations sheet, this is where I put the list of your people. You can see at the top that it automatically inserts the latest date in cell B2 then in C2 it gives you the prior month date, same in D2. Now the vlookups return the appropriate values and your graph in the graph sheet automatically updates without you having to reformat the graph or point it to different cells.

ok, so here is the final version. So, I made up data and put it into the "new data" worksheet. If you copy this column and insert copied cells into the data sheet in column C, you will see that the graph will automatically update with the new results. Beyond that you'll need to better define what you want with sample results.