Deductions & credits

OK I found one suggestion on-line that answers my earlier post.

I would use the land/total property ratio determined by the county assessor.

However, I would not use those exact values for reporting on lines 37 & 38 since they are only used for property tax calculations (i.e. not what I would use for the cost basis or FMV).

 

Now here is my follow up question:

-If home was purchased in 1998 at $217,500

-but started business use of home on 1/01/2021

 

Is the lesser of the cost basis of home/land or FMV of home/land used for reporting on line 37 & 38 based on the 2021 values or the original purchase price in 1998 (even though I started using it for business use in 2021)?

 

Thanks.