Limit time between two dates

I enter a start date in column A and a exepted finish date in column B. I want to limit the time between those 2 dates to 6 week.

Exemple:

When I enter 01/01/2016 in column A, that the date in column B can not exced 12/02/2016. And when, that a message appear you exceed the maximum time. I know that I can do this with a formule, but I prefer a vba because so I can protect the vba with a pw. If I use the formula the operators will delete the formule and enter a new date.

Thanks for help.

Hello walruseggman,

First thanks for reply. Works great, but is there also a way to force the user to enter a date in column B? Now they can tab to the other cell an continue their entries without a due date.

Thanks m8

Thanks m8.
Perfect.

Hello walruseggman.
Sorry to reopen this thread, but I have a little problem which I only discover now in the daily use. In fact when input box pops up to force a date in column B and because I live in Europe I enter the date dd/mm/yyyy and when I click ok it appears in mm/dd/yyyy. The cell is correctly formated. Is there a way to solve this?
Thanks for your help.

Thanks for your reply.
This don't work. It enter it in the right way dd/mm/yyyy, but it don't recognize it like a date, at least in my opinion, because it even accept dates exceeding the 6 weeks.

I marked this thread as solved. For possible solution follow this thread http://www.excelforum.com/excel-prog...ox.htmlhttp://