For rental income on renting a room in my house I had to put down rental value. How do I calculate the rental value for depreciation?

[kelsey-w-randall]

Would the original rental value be a percentage of the cost of my home? Say if the room is 10% of the house, would the rental value be 10% of the amount I paid to purchase the home?

[AnnetteB]

Yes, for depreciation you would need to know the cost of your home and the fair market value when it (or a part of it) was placed in service as a rental property.  The lower of the two values is the one that will be used for depreciation.

For your example, if 10% of the house is rented, then 10% of the cost or FMV will be used as the basis for depreciating the rented portion.