Why can't I add a trendline to a chart in Excel 2007?

Question

I created a really simple chart based on 2 columns (date and numeric value).
I click on the chart, go to Chart Tools/Layout. The Trendline drop down is greyed out.

What am I missing?

Answer 1

You need to make sure your dates are proper Excel dates, not just text representation of dates.

An easy way to test this is select your dates in the column and press Control + 1 to format them as numbers. If all the cells turn to numbers then you have proper Excel dates. If they still show as dates then they are text representations of dates and you'll need to convert before you can create a trendline.