Deducting the Business Use of Your Car

You can deduct the cost of using your car for business in one of two ways: the standard mileage rate (a flat cents-per-mile amount the IRS sets each year, multiplied by your business miles) or the actual expense method (your real costs — gas, repairs, insurance, depreciation or lease payments, and more — multiplied by the percentage of the time you used the car for business). You pick one method, and for a car you own, the choice you make in the first year the car is used for business affects which options stay open to you later.

Neither method lets you deduct the drive from home to your regular workplace — that's commuting, and it's personal, not business. And under either method, the IRS expects you to be able to back up your business-use claim with a contemporaneous mileage or usage log, not a guess made at tax time.

The two methods, in plain terms

1. Standard mileage rate

You track your business miles for the year and multiply by the IRS's standard mileage rate. That rate is set annually and changes — do not rely on a number you remember from a prior year or from this article; confirm the current-year rate on irs.gov before you file. The rate is meant to approximate the average per-mile cost of owning and running a car (gas, maintenance, depreciation, insurance), so once you use it, you generally can't also deduct those same actual costs separately — though parking fees and tolls for business trips are deductible in addition to the mileage rate, under either method.

This method is simpler: no receipts to sort through, just a mileage log. Many self-employed people and small businesses use it for that reason.

2. Actual expense method

You add up what it actually cost to own and run the car for the year — gas and oil, repairs and maintenance, tires, insurance, registration fees, lease payments (if leased), and depreciation (if owned) — and then deduct the share of that total that matches your business-use percentage. If you used the car 60% for business, you generally deduct 60% of each of those costs.

This method takes more recordkeeping — you need receipts and records for everything — but it can produce a bigger deduction in some situations, particularly with a higher-cost vehicle, high actual operating costs, or a high business-use percentage relative to total miles driven. There's no way to know which method wins for you without actually running the numbers both ways for your situation, ideally with a tax professional.

Why your first-year choice matters

If you own the car (rather than lease it), the IRS generally requires you to choose the standard mileage rate, if you're going to use it at all, in the first year the car is placed in service in your business. After that first year, you can switch back and forth between standard mileage and actual expenses in later years (with some depreciation adjustments if you switch), as long as you started with standard mileage.

But if you start with the actual expense method in year one — for example, because you claimed accelerated depreciation or a Section 179 deduction on the car — you are generally locked out of the standard mileage rate for that vehicle for the rest of its use in your business.

That's the practical reason many small-business owners choose standard mileage the first year even if they're not sure it's the bigger deduction: it keeps both doors open going forward, while starting with actual expenses can close one of them.

If you lease the car, the rule is different: once you choose the standard mileage rate for a leased vehicle, you generally must stick with it for the entire lease period, including any renewal.

Commuting isn't deductible — mixed use isn't automatic

The drive between your home and your regular place of business is a commute. It's a personal expense under federal tax law no matter how you use the car the rest of the day, and neither method lets you deduct it. Trips between job sites, to meet clients, to pick up supplies, or to a temporary work location are generally business miles; the ordinary commute is not.

If you use the same vehicle for both business and personal driving — which is the normal case for most sole proprietors and small-business owners — you only deduct the business-use share. That's true whether you're using standard mileage (only business miles count in the multiplication) or actual expenses (you prorate every cost by your business-use percentage). You cannot deduct 100% of a mixed-use vehicle's costs just because the business owns it or pays for it.

What to do: keeping a log the IRS will accept

Whichever method you use, keep a written or digital mileage/use log, kept close to the time of each trip (not reconstructed months later), that shows:

• The date of each business trip
• Where you went and the business purpose
• The miles driven for that trip
• Your odometer readings at the start and end of the year (to establish total annual mileage, which lets you calculate your business-use percentage)

If you're using the actual expense method, also keep receipts for gas, repairs, insurance, registration, lease payments, and anything else you're deducting, organized by year. A simple notebook, spreadsheet, or mileage-tracking app all work — what matters is that the record is contemporaneous and specific, not a lump-sum estimate at tax time.

Heavy vehicles and Section 179 — the high-level picture

Section 179 lets a business elect to deduct the cost of qualifying equipment — including some vehicles — in the year it's placed in service, rather than depreciating it over several years. A few things are durable and worth knowing even without current dollar figures:

• Ordinary passenger cars used for business are subject to "luxury auto" depreciation limits that cap how much of the vehicle's cost you can deduct per year, including under Section 179.
• Heavier vehicles — generally those rated above 6,000 pounds gross vehicle weight — are treated differently. Trucks, vans, and SUVs above that weight threshold can qualify for a much larger first-year deduction, though SUVs in that weight class are still subject to their own separate, lower cap that regular trucks and vans without rear seating are not.
• To use Section 179 at all, the vehicle generally must be used more than 50% for business. Business use at or below that threshold disqualifies the vehicle from Section 179 and generally limits you to slower, straight-line depreciation instead.
• The overall dollar limits, phase-out thresholds, and the SUV-specific cap change from year to year. Do not rely on a number you've seen elsewhere — confirm the current figures on irs.gov (Publication 946) or with a CPA before you buy a vehicle expecting a specific deduction.

Because vehicle depreciation and Section 179 rules interact with the standard-mileage-vs-actual-expense choice described above, buying a vehicle for its tax deduction potential — especially a heavier vehicle — is a good time to talk to a CPA before you sign, not after.

A note on entity type and self-employment

These deduction methods work the same way whether you're a sole proprietor filing Schedule C, a partner, or an owner of an S corporation or C corporation — though how the deduction flows through your return differs by entity type, and if your business reimburses you (the owner) for using your personal vehicle rather than the business owning the vehicle, different accountable-plan rules can apply. If you're self-employed, remember that your net business income, including vehicle deductions taken correctly, factors into your self-employment tax (Social Security and Medicare) as well as income tax — a good reason to get this deduction right rather than aggressive.

When to get help

A CPA or tax preparer can run both methods against your actual numbers, help you time a vehicle purchase around Section 179 and depreciation rules, and make sure your log will hold up if the IRS ever asks. The IRS's own free resources — Topic 510, Business Use of Car, and Publication 463 — walk through both methods in detail, and your local Small Business Development Center can point you toward free or low-cost help if hiring a CPA isn't in the budget yet.

This is general business and tax information, not legal, tax, or financial advice, and using it does not create an attorney-client or accountant-client relationship. For guidance specific to your vehicle, business structure, and situation, talk to a qualified CPA or tax attorney.