If a married couple files 1120S, how to get the home office deduction? Use the simplified method ($5 / sq foot) on 1120S or Schedule C? Deduction go on personal return?
If Schedule K-1 came from Form 1120S, S corporation shareholders generally cannot deduct unreimbursed business expenses with Schedule K-1 because the shareholders are categorized as employees when performing services for the corporation (and a corporate officer may be considered a statutory employee).
These expenses, if not subject to reimbursement from the corporation, are unreimbursed employee business expenses treated as miscellaneous itemized deductions subject to the 2% of the adjusted gross income (AGI) floor.
In this case, enter the home office expenses under Deductions & Credits >> Employment Expenses >> Job-Related Expenses.
For more from the IRS, see: S Corporation Employees, Sharholders and Corporate Officers
Just a heads up that there are two typos related to the hyperlink to: "S Corporation Employees, Sharholders and Corporate Officers." Besides the misspelled "Sharholders" in the text, the underlying URL contains a superfluous "%26-" between "Small-Businesses" and "Self-Employed" which causes the link to fail. Removing these four characters will get you there.