Here in Colorado it's common for people to both rent out a property and use it for personal purposes. This could be the case with a vacation rental or in a situation where you're renting a portion of your home but using the other portion for personal purposes.  IRS rules state that if the rental use is less than 15 days, this is not income and expenses are not allowed. If the rental use is more than 14 days, then you must report the rent income and you can report the proportional expenses against this income. If it was a vacation rental, use the days rented and the total days used to determine the rental portion of expenses. If it was your home that you were renting a portion of, you can use the square footage of the portion rented compared to the total square footage of the home, or the number of rooms rented compared to the total number of rooms in the home. Note that shared areas are considered personal use. If personal use of the property is more than 14 days or 10% of rental days, whichever is greater, then you cannot take a loss on the rental activity (expenses cannot exceed income).