I have income from apartment I own (out of the US).
I want to take into account the property depreciation.
Depreciation is calculated only on the building and not on the land.
I know the value of the property – but I don’t know how to distinguish between land value and building value.
As it is an apartment in a building - can I assume that the price is only for the building and not for the land?
Yes, if you do not own the apartment building in its entirety then you can assume that it has a land value of zero.