It's been a while since I did Excel interactions, but I recall using the xlLastCell special cell. For example:

# Get the last cell for the sheet (address returned as absolute)
my $last_cell = $worksheet->Range("A1")->EntireColumn->SpecialCells(xl
+CellTypeLastCell)->{Address};
my ($max_column, $max_row) = $last_cell =~ /\$(\w+)\$(\d+)/;

[download]

Whether or not that's the most efficient way to do it... I don't know. I do also know that with some spreadsheets I ran into some very odd values -- the spreadsheet wasn't particularly large, but the last cell was reported as IT3991 or similar.

Added:
Some of the replies in this SoPW have similar approaches. Specifically, bmann's response seems to be a cleaner bit of code than my sample above.

In reply to Re: Win32::OLE Excel LastCol not working consistently by Nkuvu
in thread Win32::OLE Excel LastCol not working consistently by uvs

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