This answer string appears to be the most correct. TurboTax DOES NOT enter an adjusted mortgage interest amount in Schedule A for the personal use portion of a rental property. I followed the advice in this string and did my own pro-ration for Schedule A, checking the box that states the amount differs from the 1098 and adding the requested note on the next screen explaining why. I do find it odd that TurboTax not only does the proration for the real estate taxes, but gives you bold reminders that it has done so; however, the app does not do the same for mortgage interest.
You will report the mortgage interest as an expense for a property that is used solely as a rental. It is not reported as an itemized deduction.
"To be clear, I rented a room (10% of sq ft) in my house for 95 days in 2019. "
Question, so if any expense (x) put is for the entire year (say property tax), the correct portion to be put to schedule E should be x * 10% * (95/365) ?
You are correct. The 10% accounts for the square footage, and the (95/365) accounts for the time it was rented.
You will report the mortgage interest for your rental property as a expense.
Where do I enter (and what percentage of) mortgage interest and property tax if my main residence is partially rented (67% rented, 33% personal)? Rental expenses, or deductions?
You would enter this information for the rental portion of your house
If 67% of your personal residence is rented, then you can deduct 67% of the mortgage interest, property taxes, utilities, internet, etc. You can also depreciated 67% of the cost of the house.
The other 33% of the house you enter the property taxes and mortgage interest in the Deductions and Credits, Your Home, Mortgage Interest, in TurboTax.