We bought a house Aug 24, 2020 which we lived in until we left for FL on Oct 29. The house began short term rental activity around Thanksgiving. Since we didn't own the house until Aug 24, not sure how to classify our ownership % for purposes of dividing expenses. TurboTax doesn't seem to offer correct options on this. We 100% owned the house from Aug 24-Dec 31, 2020. We departed for FL Oct 29. It was rented at fair market value for about 24 days in 2020. How can I get TurboTax to allocate expenses between personal and rental-related for this partial year of ownership?
Since you purchased the house in August and used it as your residence until the end of October, the expenses you incurred during that time are personal expenses and will not be reported in the Rental Income and Expenses section of your return. During that time frame the house was not a rental property. Instead, the applicable mortgage interest and property tax for that period of time can be claimed on Schedule A Itemized Deductions.
The property was converted to a rental property on October 29th. After that date, the expenses you incurred are considered to be rental expenses and would be entered into the Rental Income and Expenses section of your return to be reported on Schedule E.
Unless you used the property for personal purposes after it was converted to a rental property then there is no need to prorate the expenses within TurboTax. You will instead only enter the expenses that were incurred after it was converted to a rental.