Perhaps this example would help, which shows how to keep a chart pointed at the last
12 months of data:

http://peltiertech.com/Excel/Charts/DynamicLast12.html

- Jon
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Jon Peltier, Microsoft Excel MVP
Peltier Technical Services
Tutorials and Custom Solutions
http://PeltierTech.com/
_______

Shanin wrote:

I've looked at some examples but found myself lost. I have a sheet that
shows overtime by department (those being the rows) by month (columns), and
wanted to make a chart that will show a rolling three months for each
department, so it would show August, July, and June, and next month Sept,
Aug, July. I know I have to use the Name function and Offset in some terms
but am somewhat lost. The department names start in A7 and go down, the
months start B4 and go across. Any help would be appreciated.