Home Office Deduction for Mobile Mechanics: When It Qualifies, the $5/sq ft Method, and Why It Makes Your First Drive Deductible
Updated 2026-10-17. Sources are listed at the end.
Mobile mechanics fix cars at the customer’s place, but the quoting, ordering, scheduling and bookkeeping usually happen at home. The IRS says a home office can be your principal place of business in that situation, and qualifying affects two deductions: the office itself and your mileage.
The test: admin work at home, nowhere else fixed
Under IRS Publication 587, a home office qualifies as your principal place of business if (IRS Pub. 587):
- you use it exclusively and regularly for administrative or management activities of your business, and
- you have no other fixed location where you do substantial administrative or management work.
The IRS example is close to a mobile tech’s situation. Sid, a self-employed plumber, spends most of the time at customers’ homes and offices, and uses a small home office “exclusively and regularly” for phoning customers, ordering supplies and keeping the books. Sid writes estimates and records at customers’ premises and uses an outside bookkeeping service. Sid’s home office qualifies (Pub. 587, Example 1). In another example, doing some admin work from a hotel room, which isn’t a fixed location, doesn’t disqualify the home office. By the same logic, writing invoices in your van between jobs shouldn’t count against you, because a van isn’t a fixed location.
Exclusive use is strict
The space must be used only for business. It can be a room or a separately identifiable area, with no permanent wall needed. In the IRS’s example of a den used for work and family recreation, the den doesn’t qualify. The only exceptions are certain inventory storage and daycare use (Pub. 587). The kitchen table doesn’t count. A desk area used only for the business can.
Garages and outbuildings: you can deduct a separate free-standing structure, such as a garage or workshop, used exclusively and regularly for your business. It doesn’t have to be your principal place of business (Pub. 587). A detached garage used only for parts and tool storage may qualify. An attached garage that also holds the family car generally fails the exclusive-use test.
Two ways to figure it
| Simplified method | Regular (actual expense) method | |
|---|---|---|
| How | $5 × business square feet, up to 300 sq ft (max $1,500) | Business % of mortgage interest or rent, insurance, utilities, repairs, depreciation |
| Paperwork | Minimal | Form 8829 for self-employed, plus records |
| Depreciation | None on the business portion that year | Yes (recaptured when you sell) |
Source: IRS Pub. 587 (simplified method under Rev. Proc. 2013-13). With the simplified method you can’t also deduct actual home expenses for that space, though business expenses unrelated to the home, like your phone line or software, stay deductible.
Example: a 10 × 12 ft office (120 sq ft) × $5 = $600 deduction under the simplified method.
The mileage effect
IRS Publication 463 says that if your home office qualifies as a principal place of business, “you can deduct your daily transportation costs between your home and another work location in the same trade or business” (IRS Pub. 463). For a mobile mechanic, that means the first drive of the day to a customer counts as business mileage, not commuting. At 76¢ a mile (July-Dec 2026), that’s often worth more than the office deduction. See mileage deductions for mobile mechanics.
Records to keep
- A floor sketch with measurements and photos of the space set up for business
- Evidence of regular use: invoices, supplier orders and your scheduling app all show activity from that address
- A mileage log that starts at home
- For the regular method, the home’s expense bills and basis records
Put the deduction in context with the rest of your taxes: quarterly estimated taxes, QBI deduction, and tool and van deductions.
Sources
- IRS, Publication 587 (2025), Business Use of Your Home: https://www.irs.gov/publications/p587
- IRS, Publication 463 (2025), Travel, Gift, and Car Expenses: https://www.irs.gov/publications/p463