Where do you input the cost of room and board to reduce the tax due from a 529 distribution?

Two options:

1. If part of the Q will be taxable, enter the Q first then add the expenses. As you go through the program, it will ask about room and board.

2. If the Q is fully used on  529 qualified Room and Board (including students living at home) and Qualified Education Expenses - Internal Revenue Service  then the nontaxable transaction should not be entered.  IRS Publication 970, Tax Benefits for Education states:

Page 45: Don't report tax-free distributions (including qualifying rollovers) on your tax return.