I live in a 3 bedroom house and am currently renting 2 bedrooms, but my roommates have access to the entire house. Can I deduct 2/3 of my expenses again the income?

[stephanie2]

I've seen that the two most common ways to divide expenses like mortgage interest or taxes are either square footage or number of room, but I'm not clear if number of rooms means bedrooms or not. They have access to and use the whole house, so I'd like to deduct 2/3 of those expenses since there are three of us. 

[Jennifer-BrownDC]

Maybe -- but it depends on the total number of rooms (not just bedrooms) you have in the house. Assuming you have a total of 6 rooms: the three bedrooms, one bathroom, a kitchen, and a living/dining room area, then you can take 100% of the two rented rooms and 2/3 of each of the shared rooms.  So that is:

 2 (rented rooms) + 2/3 of 3 rooms = 4/6, or 2/3 (67%).   

If, however, you have 2 bathrooms and one is just for you, then you have 7 rooms, but can still only add 2/3 of the three shared rooms:  

2 (rented rooms) + 2/3 of 3 rooms = 4/7 =  57%.

You can, however, probably deduct 2/3 of utility costs if you are all around roughly the same amount of time.