What are other methods for dividing expenses when renting room in my home besides square footage and number of rooms?

[whitehorses8523]

According to the IRS, if you rent part of your home, the most common methods for dividing an expense are based on the number of rooms in your home or based on the square footage of your home.

I rent a bedroom in my house.  My roommate shares most of the rest of the house too (e.g kitchen, living room), so it does not seem accurate to just use the square footage of his bedroom or one room out of the whole house to determine expenses.  What are some less common methods for dividing expenses that would be acceptable?

[Vanessa]

You can also use the number of people in the house to divide expenses.  So if it is just you and the other person then you would split the expenses 50/50. If you have a child and rent to one person then it would be 33% to the renter since they would be 1/3 of the people in the house.