Turbotax does not seem to prorate home office expense correctly

[hxia11]

I started using my home office for my business since August 2025, the home office accounts for 11% of the home living area, to my understanding, the correct formula should be total_expense * 11% * portion_of_year_used_for_home_office.

However, Turbotax does not seem to factor in the last factor even through I explictly entered the first day used for business and number of month used for more than 15 days. I tried to toggle the date and it does NOT affect the outcome, it seems Turbotax is defaulting the home office for the entire year.

[rjs]

Duplicate question. Please post your question only once.

[hxia11]

I have asked the moderator to remove the original post as it was posted under the wrong topic

[rmunson8]

I am seeing the same issue. I only used my home office for 2 months out of the year.  When I go through the guided tour for home office expenses, it ask when I started to use the home office and the number of months I use it at least 15 days (I entered 11/10/25 and 2 months).  It then asks for full year amounts for each respective expense (home mortgage interest, utilities, etc).  But upon completion it only prorates it by the sq footage % but not by the number of months used out of the entire year.

The workaround of course is to manually enter those values and prorate myself, but that definitely is going to confuse many users.  Known issue?