I rent one of the rooms in my apartment with AirBnB and I count it as 20% of my apartment. Can I deduct 20% of the rent that I pay to my landlord, as an expense?

[KittyM · Accepted solution]

Yes, you can.  You are entitled to deduct all ordinary and necessary expenses to operate your AirBnb. Think of your rental as a bed-and-breakfast. You may deduct direct costs, such as new towels or sheets, repainting the guest bathroom, or putting out snacks.  You may also deduct expenses such as rent and utilities.  

However, "if you use your house for both rental and personal purposes, you generally must divide your total expenses between the rental use and the personal use based on the number of days used for each purpose. You won’t be able to deduct your rental expense in excess of the gross rental income limitation.

Example: You used an online app to rent a room in your house 73 days last year, or 20% of the year. The room is 12 × 15 feet, or 180 square feet. Your entire house has 1,800 square feet of floor space. You can deduct as a rental expense 10% of any expense that must be divided between rental use and personal use, divided again by the percentage of the time the room was available for rent during the year. If your heating bill for the year for the entire house was $600, $12 ($600 × .10 × .20) is a rental expense. The balance, $588, is a personal expense that you cannot deduct."

The above is a quote from the IRS' Sharing Economy Tax Center.  The whole article is at https://www.irs.gov/businesses/small-businesses-self-employed/sharing-economy-tax-center