Will my 401k loan be counted in my DTI?  401k loans are not counted in most instances in your DTI(debt to income ratio), because they consider them loans secured against your own assets.  Normally, when you take out a 401k loan, that money is put on hold and you earn a rate equal to the rate of the loan.  Basically, you are borrowing from yourself.   If you leave employment or default, then that amount is available for distribution from your account. 

You can use the funds that you have borrowed from your 401k for your down payment and closing costs.  However, the asset securing the loan may not be included as assets to close or otherwise considered as available to the borrower. 
 
Additionally, keep in mind that there are some lenders that have "overlays" (guidelines above and beyond what FHA and Fannie Mae require) who will count them in your debt ratio.  It's essential to disclose to your lender upfront if you have a 401k loan and ask  what their policies and guidelines are.  That way there are no surprises during underwriting.