Calculate days in month after a given date

Hi DonkeyOte,

Please see attached file. I have attempted to include an end date column, however have missed something. It now appears to do some kind of funky calculation in the month that the end date occurs, and then has a standard figure for any months following.

I dont quite have the way the date functions work down pat yet, and any guidance would be greatly appreciated.

Thanks
Darren.