Dividing Rental and Personal Expenses
If you use a dwelling unit for both rental and personal purposes, divide your expenses between
the rental use and the personal use based on the number of days used for each purpose.
Rules for dividing expenses between rental and personal uses
When dividing your expense, follow these rules:
Count any day the unit is rented as a day of rental use even if you used it for
personal purposes that day.
Do not count as a day of rental use any day the property is available for
rent but not actually rented.