The home office deduction, without the red flags

Who can take it

The home office deduction is for people who work for themselves: sole proprietors, single-member LLC owners, independent contractors, and partners in some cases. Sole proprietors claim it with Schedule C, usually through Form 8829.

If you’re a W-2 employee, you can’t deduct home office costs on your federal return, even if your employer requires you to work from home. The One Big Beautiful Bill Act made that rule permanent. Some states allow employee business expenses, so it can still matter on a state return.

If you own an S corporation or C corporation, you’re an employee of your company, and the route is different. The company reimburses you for the business share of your home costs under a written accountable plan. The reimbursement is deductible to the company and tax-free to you, and you don’t claim anything on your personal return.

The two tests the space has to pass

Most problems come from the first test. Examiners ask about it directly, and the answer needs to be simple and true.

• Regular and exclusive use: the area is used only for business, on a consistent basis. A desk in the guest room that doubles as a guest bed doesn’t count. A room, or a clearly defined part of a room, used only for work does.
• Principal place of business: it’s where you do most of your work, or where you handle administrative and management tasks (billing, scheduling, bookkeeping) and you have no other fixed location where you do substantial amounts of that work.
• Alternatives: a space where you regularly meet clients or patients in the normal course of business, or a separate freestanding structure like a detached studio used for business, can also qualify.
• Exceptions to exclusive use: certain licensed daycare use, and storage of inventory or product samples in a separately identifiable space when your home is the business’s only fixed location.

The simplified method

The simplified method is $5 per square foot of qualifying space, up to 300 square feet, for a maximum of $1,500 a year. There’s no depreciation to track and no allocation of bills.

A 200-square-foot office produces a $1,000 deduction. Your mortgage interest and property taxes stay entirely on Schedule A if you itemize, since none of them are allocated to the business.

The trade-off: the deduction can’t exceed the business’s gross income limit, and anything over that limit is simply lost rather than carried forward.

The regular method, worked through

The regular method uses your actual costs. You figure the business percentage of your home, usually office square footage divided by total square footage, and apply it to indirect expenses like mortgage interest, property taxes, insurance, utilities, general repairs, HOA dues, and depreciation if you own the home. Direct expenses, such as painting the office itself, are deductible in full.

Example: a 250-square-foot office in a 2,500-square-foot home is 10% business use. With $18,000 of mortgage interest, $9,000 of property taxes, $2,400 of insurance, $4,800 of utilities and $1,200 of general repairs, the business share is $3,540.

Depreciation adds to that. The business part of a home is depreciated as nonresidential real property over 39 years, based on the building’s cost or value when you started using it for business (whichever is less), not the land. If the building portion is $500,000, the office share is $50,000, which works out to about $1,280 a year after the first partial year. Combined, that’s roughly $4,800, compared with $1,250 under the simplified method.

If you rent, the business share of rent replaces mortgage interest, taxes and depreciation. A 10% office in a $3,500-a-month apartment is $4,200 of rent alone.

The income limit and carryovers

Under either method, the deduction can’t create or increase a business loss. The IRS applies it in a set order: first the business share of mortgage interest and taxes, then other business expenses, then operating costs of the home, and depreciation last.

If your business nets only $3,000 before the home office, the regular method lets you carry disallowed operating costs and depreciation forward to next year. The simplified method caps at the limit and the excess is gone.

You can choose a method each year. If you switch back to the regular method after using the simplified method, depreciation is figured using the optional tables for the home’s remaining recovery period.

What happens when you sell the home

This is the part people forget. Depreciation you claimed, or could have claimed, after May 6, 1997 on the business part of your home is taxable when you sell, even if the rest of your gain qualifies for the home sale exclusion ($250,000 single, $500,000 married filing jointly, if you meet the ownership and use tests).

In the example above, ten years of office depreciation would be about $12,800 of gain that stays taxable at sale. That doesn’t make the regular method a bad choice; it means the deduction is partly a timing benefit, and you should keep the depreciation schedule with your home records.

A separate structure, like a detached studio, is treated differently. Gain on that part generally can’t be excluded unless you also owned and lived in it for at least two of the five years before the sale, so the sale price has to be allocated. The simplified method, by contrast, creates no depreciation to recapture for the years you use it.

Situations that change the math

• Part-year use: if you start using the office mid-year or move, the simplified method uses an average monthly square footage, and the regular method prorates expenses by the months used.
• Two businesses in one office: each business must meet the tests, and you allocate the space between them.
• Outside office too: a physician with hospital privileges or an attorney with a firm office needs to show why the home office is still the principal place for administrative work, or that it’s used to meet clients.
• Renting part of the home to others or an upcoming sale both affect the allocation and the recapture math.
• Schedule F filers and partners use the worksheet in IRS Publication 587 rather than Form 8829.

Records that keep it boring

A well-documented home office is an unremarkable deduction. Keep it that way.

• A simple floor plan or measurements showing the office and total home square footage.
• Dated photos of the space set up for work, with nothing that suggests another use.
• Utility bills, rent or mortgage statements, property tax bills, insurance and repair receipts if you use the regular method.
• Your purchase closing statement and improvement records, which set the depreciable basis.
• A short note on why this is your principal place of business, especially if you also have access to an outside office.
• For S corp owners: the written accountable plan and the monthly or quarterly reimbursement calculations.

When to run the numbers both ways

For a small office in a modest home, the simplified method is often close enough and far less work. For a larger office, a high-cost area, or a renter, the regular method frequently produces three or four times the deduction.

When Tally Tax prepares a return with a home office, the comparison includes the sale-time recapture, not just this year’s number, and for S corp owners, it’s set up as an accountable plan reimbursement rather than a deduction on the personal return.

Frequently asked questions