Hi Rob,

When choosing a Line chart in Excel you will always get a vertical drop off after the last entry, if the "next month" is 0, (zero), or has not yet been entered. It is a nuisance and the only way I can think of changing this is to limit the x axis, (months), so that the last month is always the last for which you have data.

But that means you have to change the x axis range each time new data is entered.

My own option is to use a different chart type. I use the Area chart, 1st sub-type. This creates an area below the line which ends with the last data entry.

Not always acceptable, but worth a try to see if it works for you.