What is the cut-off date for your wedding so that you can file jointly? We got married on 15-Dec-2018, so we were curious if we can still file jointly for 2018.

The cutoff date is December 31 of the year.  If you are legally married by December 31, 2018, you are considered as married for the whole year.  You can file jointly on your 2018 taxes. 

Thanks.