Business & Tax

What Car Expenses Can You Actually Write Off?

10 min read · Updated October 2026 · Written by AutoCalcHub Team

People tend to fall into one of two errors on this. Either they assume driving for work makes the whole car deductible, or they assume none of it counts and skip the deduction entirely. Both are expensive in different directions.

Quick answer: If you're self-employed, you can deduct the business-use share of your vehicle costs — but commuting never counts, and that single exclusion is what shrinks most people's deduction. If you're a W-2 employee, current federal law generally lets you deduct nothing at all. The number that governs everything is your business-use percentage, and it has to come from a contemporaneous log, not an estimate at tax time.

First Question: Are You Even Eligible?

This gate stops more claims than any other.

Self-employed, contractor, sole proprietor, gig worker. Yes — vehicle expenses go directly against your business income, which also reduces self-employment tax. This is where the deduction lives.
Business owner (LLC, S-corp, partnership). Yes, though the mechanics differ. An S-corp typically reimburses you under an accountable plan rather than you deducting personally.
W-2 employee. Generally no. Unreimbursed employee vehicle expenses aren't deductible under current federal rules. Ask your employer for an accountable-plan reimbursement instead — it's tax-free to you and deductible to them.
Both employed and self-employed. You can deduct against the self-employed side only, for miles driven for that work.

The Commuting Rule, Which Costs People the Most

Driving from home to your regular place of work is personal travel. It is never deductible, no matter how far it is, how early you leave, or whether you take work calls on the way.

What does count:

Travel between two work locations in the same day
Trips to meet clients or visit job sites
Driving to a temporary work location outside your usual area
Errands with a business purpose — supplies, the bank, the post office

There's a significant exception. If you have a qualifying home office as your principal place of business, the trip from home to your first work location is business travel, because you're not commuting — you're leaving your office. For someone who works from home and visits clients, this can convert most of their driving from non-deductible to deductible. It's worth understanding properly rather than assuming either way.

Business-Use Percentage Runs Everything

Your business-use percentage is business miles divided by total miles for the year, and it scales your entire deduction under the actual expense method. Drive 15,000 miles of which 9,000 are business, and 60% of your vehicle costs are deductible.

That percentage also has consequences beyond the size of the deduction. If it falls below 50% after you've claimed accelerated depreciation, you can face depreciation recapture — repaying part of what you already deducted. This catches people whose business slows down a year or two after buying the vehicle.

Which Method Should You Elect?

The first-year choice between standard mileage and actual expenses is permanent in one direction.

Mileage Deduction Calculator →

What's Deductible Under Each Method

Expense	Standard mileage	Actual expenses
Fuel	Included in the rate	Business share
Insurance	Included in the rate	Business share
Repairs, maintenance, tires	Included in the rate	Business share
Registration fees	Included in the rate	Business share
Depreciation or lease payments	Included in the rate	Business share
Parking & tolls (business trips)	Deductible on top	Deductible on top
Loan interest (self-employed)	Deductible on top	Deductible on top

The last two rows are the ones people miss. Parking and tolls for business travel are separately deductible under either method, and so is the business share of car loan interest if you're self-employed. Neither is baked into the standard rate.

Note that this business-use interest deduction is a different thing from the personal car loan interest deduction created for 2025–2028, which has its own eligibility rules — covered separately here.

What Records You Actually Need

Vehicle deductions sit under Section 274(d), which imposes stricter substantiation than ordinary business expenses. In practice that means a contemporaneous log — kept as you go, not reconstructed in April.

Each business trip needs the date, destination, business purpose, and miles driven. Record odometer readings at the start and end of the year so your total-miles figure is defensible. If you're on actual expenses, keep receipts for everything you're claiming.

A mileage app that logs automatically is worth the subscription, mostly because reconstructed logs are the first thing disallowed in an audit and the deduction is often four or five figures.

Common Mistakes With Vehicle Write-Offs

Deducting the commute. The most common error and the easiest for the IRS to spot.
Claiming 100% business use on your only car. Almost never credible, and a reliable audit flag.
Estimating mileage at year end. Substantiation rules require contemporaneous records.
Forgetting parking, tolls and loan interest are deductible on top of the standard rate.
Assuming employees can deduct. Generally not under current federal law — get reimbursed instead.
Ignoring the first-year method election. Choosing actual expenses first permanently bars standard mileage on that vehicle.

This is general information rather than tax advice, and the rules around home offices, entity types and depreciation are more nuanced than a single article allows. Check your specific situation with a CPA, particularly before claiming a high business-use percentage or making the first-year method election.