My home office is in the back house of an investment property that I own. Is this still a home office? If not, how do I take deductions for this office?

[tjwalthall]

I rent the main house out to tenants, and I work out of a separate guest house in the backyard. Do I calculate deductions in a similar way to a typical home office, or should I be paying myself rent for this office and deducting that?

[Vanessa]

Neither. In order to claim a home office deduction, you would need to use your actual home to take the home office deduction. 

If you are paying yourself rent you would have to claim it as income, so you would get a deduction for it, but you would pay taxes on it the same as if you didn't get a deduction for it.

Since this is a rental property, you are likely already claiming expenses for it.  If you took expenses a second time you would be "double dipping" which is not allowed.