IRC §280A home office deduction: the exclusive-use rule, the principal-place-of-business test, the simplified method, and the depreciation recapture that catches people on sale

IRC §280A starts from a general rule: no deductions are allowed for expenses of a dwelling unit used as a personal residence. The provision was enacted in 1976 to shut down tax sheltering through vacation rentals and home-office claims that had gotten out of hand. The general disallowance is broad. Section 280A(c) then carves out specific exceptions, and those exceptions are the framework that lets self-employed people, independent contractors, and small business owners deduct legitimate home office expenses.

The framework is highly technical, the tests are strictly applied, and a substantial number of taxpayers who claim home office deductions on Schedule C are exposed to disallowance on audit. The IRS does not audit home office claims as aggressively as it once did (the simplified method, introduced in 2013, defused much of the historical compliance concern), but the substantive rules are unchanged and the exposure is real for taxpayers using the regular method on substantial deductions.

What §280A disallows

§280A(a) states the general rule: no deduction otherwise allowable under the Code shall be allowed with respect to the use of any dwelling unit used by the taxpayer during the taxable year as a residence.

The disallowance reaches the full range of dwelling-related expenses: depreciation, utilities, insurance, repairs, mortgage interest (to the extent allocable to the business-use portion), real estate taxes (similarly allocable), security systems, lawn care to the extent business-related, and so on. Without §280A's exceptions, none of these would be deductible at all for a residence; the exceptions are the mechanism that makes home office deductions possible.

"Dwelling unit" includes a house, apartment, condominium, mobile home, boat, or similar property providing basic living accommodations. It includes "appurtenant structures" used in connection with the dwelling: detached garages, sheds, separate guest houses, and so on. For a person whose home and office are physically intertwined, the entire structure is the "dwelling unit" for §280A purposes.

"Used as a residence" generally means the taxpayer uses the unit for personal purposes for more than 14 days during the taxable year, or 10% of the days the unit is rented at fair rental value, whichever is greater. Most home office situations involve a primary residence that's used for personal purposes year-round, so the residence threshold is easily met.

The §280A(c) exceptions

§280A(c) provides four substantive exceptions to the general disallowance:

Exclusive and regular use as principal place of business

Per §280A(c)(1)(A), a portion of the dwelling unit used exclusively on a regular basis as the principal place of business for the taxpayer's trade or business is eligible.

The two operative tests:

Exclusive use is strict. The portion of the home being claimed must be used solely for business purposes; even occasional personal use (a guest sleeping on the office couch, the kids using the desk for homework) defeats the exclusivity. The IRS audits this question by asking what else happens in the space, and the answer "nothing personal" must be substantively true. A separately designated room is the safest framework; a corner of the kitchen used for business is not.

Regular use means the space is used for business on a regular basis. Occasional or incidental business use does not qualify. The standard is what a reasonable person would call "regular," not a fixed number of hours per week.

Principal place of business is defined in §280A(c)(1) and clarified in Commissioner v. Soliman, 506 U.S. 168 (1993) and the 1999 regulations that followed. The taxpayer's home office is the principal place of business if (1) the office is used exclusively and regularly for administrative or management activities of the taxpayer's trade or business, and (2) there is no other fixed location of the trade or business where the taxpayer conducts substantial administrative or management activities of the trade or business.

The 1999 regulation effectively reversed Soliman and made the test workable for service professionals (doctors, real estate agents, sales reps) who do their substantive work at client locations but handle administrative tasks at home. Under the current framework, a home office used for billing, scheduling, record-keeping, and other administrative functions can be the "principal place of business" even if the taxpayer spends most working hours elsewhere.

Exclusive and regular use for client/patient meetings

Per §280A(c)(1)(B), a portion of the dwelling used exclusively on a regular basis as a place of business used by patients, clients, or customers in meeting or dealing with the taxpayer in the normal course of the trade or business is eligible.

This exception is narrower than the principal-place-of-business exception. The meeting must be in the normal course of the trade or business; occasional client meetings at home do not qualify if the substantive client meetings happen elsewhere. The space has to be used for client meetings on a regular basis.

Separate structure

Per §280A(c)(1)(C), a portion of the dwelling that is a separate structure not attached to the dwelling unit, used in connection with the taxpayer's trade or business, is eligible.

This is the most permissive of the substantive exceptions. A detached garage converted to a workshop, a backyard studio, a separate building on the property used for business: any of these qualify if used in connection with the trade or business. The exclusive-use requirement still applies, but the test for what the use connection is, is more flexible than the principal-place test.

Storage of inventory and product samples

Per §280A(c)(2), the storage of inventory or product samples on a regular basis qualifies, provided that (1) the trade or business sells products at retail or wholesale, (2) the dwelling unit is the sole fixed location of the trade or business, and (3) the storage space is used regularly. The exclusive use requirement does not apply to inventory storage. This exception is narrower in scope (limited to retail/wholesale businesses with no other fixed location) but the exclusive-use waiver makes it easier to qualify.

The simplified method

Effective for tax years beginning in 2013, the simplified option under Rev. Proc. 2013-13 allows a taxpayer who otherwise qualifies under §280A(c) to deduct $5 per square foot of qualified business use, up to 300 square feet, for a maximum simplified deduction of $1,500.

The simplified method has substantial advantages:

No depreciation calculation. The home is not depreciated during years the simplified method is used.

No depreciation recapture on sale for years the simplified method was used.

No allocation of utilities, insurance, taxes, or other actual expenses.

No record-keeping for actual expenses beyond confirming square footage.

The disadvantages:

Capped at $1,500 even for substantially larger home offices.

No carryover of losses (the gross-income limitation under §280A(c)(5) still applies, but losses cannot be carried forward).

Cannot use the simplified method for one home in a year and the regular method for another, though you can switch methods year over year.

For taxpayers whose qualifying home office is around 300 square feet or less, and whose actual expenses are modest, the simplified method is generally the better choice. For taxpayers with larger offices, substantial actual expenses, or who own a home with significant property tax and depreciation potential, the regular method may produce a substantially larger deduction.

The regular method

The regular method allocates actual expenses to the home office based on the percentage of the home used for business. The standard allocation is by square footage: if 200 square feet of a 2,000 square foot home are used as a home office, 10% of the home expenses are allocated to the business.

The allocable expenses include:

Direct expenses that are entirely for the home office: a paint job on the office walls, a separate phone line, business-specific furniture. These are 100% deductible.

Indirect expenses that benefit the entire home: utilities, insurance, security, lawn care, general repairs. These are allocated by the business-use percentage.

Depreciation on the home itself, allocated to the business-use portion. The home is treated as 39-year nonresidential real property for the business-use portion (not the 27.5-year residential framework that would apply if the whole home were a rental). This is where the regular method generates substantial deductions but also produces the depreciation recapture issue discussed below.

Mortgage interest and real estate taxes allocable to the business-use percentage. These would otherwise be deductible on Schedule A as itemized deductions; the §280A allocation moves the business portion to Schedule C.

The §280A(c)(5) gross income limitation

This is the provision that catches taxpayers using the regular method on a home office for a business with modest income.

§280A(c)(5) caps the home office deduction at the gross income from the business activity, reduced by deductions allocable to that gross income that are otherwise deductible (regardless of the home office). In practice, the gross income limit is reached by stacking the deductions in a specific order:

First, deductions allowable regardless of business use of the home (the portion of mortgage interest and real estate taxes that would be deductible on Schedule A anyway).

Second, deductions for business expenses that are not allocable to the home (supplies, advertising, professional fees, etc.).

Third, home office deductions other than depreciation (utilities, insurance, indirect expenses).

Fourth, depreciation on the home.

The deductions allowed in each tier are limited by what's left of gross income after the prior tier. Depreciation on the home is the deduction that gets squeezed first; if gross income runs out before depreciation is fully deductible, the depreciation is carried over to a future year (rather than allowed in the current year).

The carryover is indefinite. A home office that loses money in 2026 (under the gross income limit) can deduct the disallowed amounts against home office income in 2027 or any future year.

Depreciation recapture on sale

If you took home office depreciation under the regular method in any year, the depreciation taken is subject to recapture under §1250 when you sell the home. The recapture is taxed at a maximum rate of 25% (the unrecaptured §1250 gain rate), and it applies regardless of whether the home qualifies for the §121 home sale exclusion ($250,000 single / $500,000 married filing jointly for the personal-residence portion).

The §121 exclusion is allocated by the business-use percentage. The business-use portion of the gain does not qualify for §121 and is fully taxable (with depreciation recapture as a component).

This is the substantial financial consideration that the simplified method was designed to address. A taxpayer who took $20,000 of home office depreciation across 10 years using the regular method, and who sells the home for $250,000 of gain, faces $5,000 of depreciation recapture tax in addition to the regular gain analysis. The simplified method avoids this entirely.

The TCJA W-2 employee carve-out

The 2017 Tax Cuts and Jobs Act suspended the miscellaneous itemized deduction for unreimbursed employee business expenses through 2025. W-2 employees who work from home cannot deduct home office expenses on their personal returns during this period; the deduction only applies to self-employed taxpayers, statutory employees, and certain employer reimbursement frameworks.

The TCJA suspension is scheduled to expire at the end of 2025, which would in theory restore employee home office deductions for 2026 and forward. As of early 2026, Congress had not enacted permanent extension, so the W-2 home office deduction is currently available again under pre-TCJA rules for 2026 tax years. Verify the current status before filing.

How §280A interacts with other small business provisions

The framework coordinates with several other provisions covered in the Halstonberg small business pillar:

§168 MACRS depreciation governs the recovery period for the home office portion (39 years as nonresidential real property).

§263(a) capitalization determines which home office improvements are capitalized versus deducted as repairs.

§179 immediate expensing is not available for home office depreciation on the building itself (real property), but is available for furniture and equipment used in the home office.

§199A QBI deduction requires reducing QBI by the deductible home office amount; the home office deduction is a Schedule C deduction that flows into the QBI calculation.

§1411 NIIT does not generally affect Schedule C net income from active trades or businesses, so the home office deduction doesn't directly interact with NIIT for self-employed taxpayers in active businesses.

Practical guidance

For self-employed taxpayers considering the home office deduction:

The exclusive-use test is the most-failed of the qualifying tests. If you use the space for anything personal, you do not have an exclusive use. The "the kids do homework at this desk" framing defeats the deduction.

The simplified method is the right answer for most home offices under 300 square feet. The administrative burden is minimal, depreciation recapture is avoided, and the deduction is at the level most home offices would generate under the regular method anyway.

The regular method is worth the complexity if the office is substantially larger than 300 square feet, the home has substantial property tax and mortgage interest, or you anticipate selling the home with substantial gain and want to keep the depreciation recapture issue manageable.

If you use the regular method, keep a separate file documenting square footage, allocation calculations, and direct vs. indirect expenses. The IRS audit response on a home office case is documentation-driven; the file is the defense.

Plan for the depreciation recapture when you sell. If you took meaningful home office depreciation, the §1250 recapture is going to be a real tax bill at sale; build the expectation into your planning.