>>>lnDaysInMonth = GOMONTH(ldDate,1)-ldDate
>>
>>You do need those two lines, because if you're on Jan 31st, gomo(jan31,1) will give you February 29th (assume a leap year), and {feb 29}-{jan 31} would give you 29 instead of 31. Therefore, it's only safe to go back to 1st day of the month first.
>
>
>Geez, didn't anybody read my own reply to myself on this... <g>

I just didn't see how long the thread was, and when I clicked on "Send", there it was... someone else already corrected this (including yourself :).

That's the way it goes around here, the little tricks around date calculations are everyone's favorite sport, and a question like this is sure to create a looooooong thread. Did you notice how many people actually tried to create one-liners? That's another sport :)