Do I include the square footage of my basement when calculating the total square footage of my house for home office?

[lazntiml]

I use a room exclusively for my office that is 200 square feet. My house is 2,000 square feet. My basement is 500 square feet. When calculating the square footage for office, do I do 2000 as the total or 2500? (i.e 200/2000 or 200/2500).

[TaxGuyBill]

You would probably use 2500.

If it was an unfinished basement and had no heat or electricity, you might have an argument to use 2000, but I would use 2500.