The vehicle deduction is the most-disallowed Schedule C item in audits. Not because people aren't driving — because their logs don't survive scrutiny.
In 2026 the standard mileage rate is 67¢/mile (the IRS adjusts annually; check Notice 2025-X for the official 2026 rate). At 12,000 business miles, that's an $8,040 deduction. Worth doing right.
The four required fields
§274(d) and the implementing regs require a "contemporaneous" log with four pieces of information per trip:
- Date of the trip
- Mileage (or odometer start/end)
- Business purpose — specific, not "errands"
- Destination — the place you went, not just the address
Miss any one of these and the deduction can be disallowed. "Contemporaneous" means recorded at or near the time of the trip — a spreadsheet built in April from memory does not qualify.
What "contemporaneous" actually means
The Tax Court has held that a log written within a week is contemporaneous. A log reconstructed at year-end from a calendar is not. A log built on April 14 to support an April 15 return is laughably not.
The IRS auditor's checklist:
- Are entries dated in chronological order?
- Are mileage values consistent with route maps (Google distance from A to B)?
- Are business purposes specific or generic?
- Do entries cluster around tax season (a sign of reconstruction)?
GPS-based logging apps timestamp entries automatically, which is the cleanest defense.
Standard mileage vs actual expenses
Both methods require the same log. The difference is how you compute the deduction:
- Standard: business miles × IRS rate (67¢ in 2026, projected). Simple. Higher rate in low-fuel-cost vehicles.
- Actual: total vehicle costs × (business miles / total miles). Better for trucks, EVs with high depreciation, and luxury vehicles.
You can switch from standard to actual in any year. You can switch from actual to standard only if you didn't use MACRS depreciation in any prior year. Most sole props are better off staying with standard for vehicle simplicity.
For more on the choice, see line 9 in our Schedule C deductions checklist.
What counts as business mileage
Yes:
- Client meetings, on-site visits
- Bank, post office, supplier runs
- Continuing education (if business-related)
- Travel between two work locations on the same day
- Conference and trade-show travel
- Driving to a temporary work location outside your normal area
No:
- Commuting — your first trip from home to your regular place of business is never deductible
- Personal errands you happen to combine with a business stop (only the marginal business mileage counts)
- Driving for charity (different deduction, different rate, on Schedule A)
The "commuting" rule has a major exception: if your home is your principal place of business (i.e., you qualify for the home office deduction), then trips from home to a client are not commuting — they're business trips from your office.
This is one reason the home office deduction compounds: it converts every "commute to a client" into a deductible trip.
Approved logging methods
In rough order of audit-defensibility:
- GPS-based apps with automatic trip detection — MileIQ, Stride, Hurdlr, ExpenseGhost mileage. Trips are timestamped and route-verified.
- Manual app log — Trip Logger, Excel template, paper notebook. Must be filled in same-day.
- Calendar reconstruction — risky. Works only if your calendar entries include destination + purpose and are time-stamped.
- Mileage estimates from total miles — almost always disallowed.
If you choose GPS auto-tracking, review and confirm trips weekly. Apps misclassify ~5–10% of trips (a personal grocery run logged as business, for instance). The auditor will notice; pre-empt it.
Sampling: the 90-day method
Reg §1.274-5T(c)(3)(ii) lets you keep a "representative sample" — at least one full week per month, or 90 consecutive days — and apply that ratio to the year. The catch: you must establish the sample period reflects ordinary business use, and you must keep it consistently.
For freelancers with stable patterns, this is a legal shortcut. For irregular work patterns (consultants, contractors with seasonal swings), it doesn't hold up.
What auditors look for
When the IRS challenges a vehicle deduction, the path is predictable:
- They request the log.
- They sample 10–20 trips and ask for corroborating evidence (calendar entries, client emails, receipts at the destination).
- They compare claimed business miles to total odometer reading. If business miles are >70% of total, expect questions.
- They check whether you have another vehicle for personal use. If not, expect more questions.
Defenses that work: GPS-stamped logs, consistent calendar entries, receipts at claimed destinations.
Defenses that fail: "I roughly tracked it," "My phone has the location history."
How ExpenseGhost helps
ExpenseGhost can auto-detect drives from your phone's GPS and prompt you to classify each one as business or personal at the end of the day. The log exports as a clean CSV with all four required fields. See pricing.
FAQ
What's the standard mileage rate for 2026?
67¢/mile (projected; the IRS confirms in late 2025 / early 2026 via Notice). Verify before filing.
Can I switch from standard to actual mid-year?
No — you pick one method per vehicle per year. Switching happens at year boundary.
Do I need to log commute trips?
You don't need to deduct them, but logging them helps establish total miles, which is useful for the actual-expense method and for the IRS's business-use ratio analysis.
What if I lease the vehicle?
Standard mileage works for leases too. You commit to the standard method for the entire lease term, including any extensions.
What if my employer reimburses some miles?
Only the unreimbursed portion is deductible. The IRS does not let you double-dip on miles your employer paid for.
ExpenseGhost provides tax estimates and tax-ready exports. We are not a tax preparer and do not file returns. Estimates are informational — verify every number with a licensed tax professional before filing.