Home mortgage interest associated with a home office is given fully to the taxpayer or spouse on the MFJ/MFS worksheet in ProConnect Tax

When home mortgage interest is entered as an indirect expense in the Business Use of Home (8829) screen, the portion calculated as an itemized deduction on Schedule A does not split equally on the MFJ/MFS Worksheet. It assigns the entire amount to either the person associated with the home office.

ProConnect Tax assumes that if a part of the home mortgage interest is involved in a home office for either the taxpayer or spouse, then the rest of the mortgage interest would also go to the same individual.

You can instead enter only the portion associated with the home office as a Direct Expense, and the remainder in Itemized Deductions to have the remaining portion split betwene taxpayer and spouse.

1. Calculate the amount of home mortgage interest allocable to the home office by multiplying the business percentage by the total mortgage interest paid during the year.
2. Enter that amount in the Business Use of Home (8829) screen as a Direct Expense.
3. Enter the remaining portion of home mortgage interest in the Itemized Deductions (Sch A) screen.

Future changes for tax year 2026

For tax years beginning after December 31, 2025, the One Big Beautiful Bill act will make changes to the make the Deduction for Mortgage Interest by making the $750,000 acquisition indebtedness limit permanent and eliminating the the previous treatment of mortgage insurance premiums as deductible interest. These changes will go into effect in tax year 2026.