If you are an employee with a W-2, this article is not for you. For tax years 2018 through 2025 the deduction is closed to employees, and Publication 587's own flowchart ends at "no deduction" the moment the space is used as an employee.
Everyone else tends to fail this deduction in the same place — in their own head, before they read the rule.
"My office is my clients' kitchens." "I'm in the truck all day." "I see patients at the hospital." So the room where the invoicing happens goes unclaimed, year after year.
Publication 587 has a second route, and it was written for exactly those people.
The short answer
| The test | What it needs |
|---|---|
| Exclusive use | The area used only for the business |
| Regular use | Not incidental, not occasional |
| Principal place of business | Either you work there or ↓ |
| The administrative route | Admin done there, no other fixed location for it |
| Separate structure | Exclusive + regular. No principal-place test |
| Employee | No deduction, 2018–2025 |
The route most people never read
Your home is your principal place of business if both are true:
"You use it exclusively and regularly for administrative or management activities of your trade or business"
and
"You have no other fixed location where you conduct substantial administrative or management activities of your trade or business."
Note what is absent: any requirement that the work happen there. The test is about where the business is run, not where the service is delivered.
The publication names the activities — billing customers, keeping records, ordering supplies, scheduling appointments, preparing reports. A plumber at four houses a day who invoices from a desk at home is doing all five of them in that room.
And the publication goes further, listing what does not break it:
- using a non-fixed location such as a car or a hotel room;
- doing occasional, minimal administrative work somewhere else;
- having someone else — a bookkeeper, a spouse — do your admin at their location;
- doing substantial non-administrative work at another fixed location.
That last one is the whole point. Seeing patients at a hospital, laying tile in a bathroom, showing houses — none of it is administrative work, so none of it displaces your home office.
Exclusive use is where it really fails
If the administrative route opens the door, exclusive use is the step most people trip on:
"To qualify under the exclusive use test, you must use a specific area of your home only for your trade or business."
It does not have to be a whole room or be partitioned off. It does have to be an area that does not also serve the family. A desk and a filing cabinet in the corner of a spare bedroom qualifies. The dining table that is a desk from nine to five does not.
(The one real exception is licensed daycare, which is allowed to share the space — it has its own arithmetic.)
Regular use is the quieter half: "Incidental or occasional business use is not regular use."
Two methods, and the simple one is usually smaller
Simplified. "$5, the prescribed rate" × the area, and "the area you use to figure your deduction is limited to 300 square feet." The ceiling is $1,500, no records of expenses, and no depreciation — "the depreciation deduction allowable for that portion of the home is deemed to be zero."
Regular. Your business percentage of the real costs: mortgage interest, rent, insurance, utilities, repairs, depreciation. Filed on Form 8829. No cap.
A 1,600 sq ft home with a 180 sq ft office, and $22,000 of indirect costs for the year:
| Method | The arithmetic | Deduction |
|---|---|---|
| Regular | 180 ÷ 1,600 = 11.25% of $22,000 | $2,475 |
| Simplified | $5 × 180 sq ft | $900 |
| Simplified, at the cap | $5 × 300 sq ft | $1,500 |
The simplified method saves an hour of arithmetic and costs about $1,575. It earns its place when the office is small, the housing costs are low, or the records genuinely do not exist — not as a default.
Two limits worth knowing before you start
It cannot create a loss. The deduction is capped at the gross income from the business use of the home, less your business deductions unrelated to the home. The disallowed part is generally carried forward.
Depreciation returns when you sell. Gain attributable to depreciation deducted after May 6, 1997 is not covered by the home sale exclusion. That is a reason to know the number, not a reason to skip the deduction — and under the simplified method there is no depreciation to recapture at all.
The separate structure, which is easier than all of this
A studio, workshop, garage or barn that is not attached to the house has a shorter test:
"You can deduct expenses for a separate free-standing structure, such as a studio, workshop, garage, or barn, if you use it exclusively and regularly for your business."
No principal-place-of-business requirement. Exclusive, regular, done.
What to settle this week
- Name the area. A specific space, used only for the business.
- Answer the admin question, not the work question.
- Check for another fixed location doing your billing and records. If there is none, you are inside the test.
- Measure both — square feet, and a year of housing costs — before picking a method.
The deduction people talk themselves out of is the one their own invoices prove they qualify for.
Common questions
I work at customer sites, not at home. Can I still claim it?
Does doing paperwork in my truck or a hotel break it?
What does exclusive use actually mean?
What counts as regular use?
I am an employee with a W-2. Can I claim it?
Is the simplified method better?
What about a garage or a studio in the garden?
Can the deduction create a loss?
Does claiming it cause problems when I sell the house?
This article is for educational purposes only and does not constitute tax, legal, or financial advice. Consult a qualified tax professional about your situation.