Vehicle Expense Deductions: Standard Mileage Rate vs. Actual Expenses

If you use a vehicle for business, even part of the time, the miles you drive can turn into a real tax deduction. Most owners know this in general but are not sure which of the two calculation methods to use, or how to document it well enough to survive a closer look. Here is how each method works and how to decide between them.

What Counts as Business Use

Business use includes driving to meet clients, traveling between job sites, picking up supplies, banking trips for the business, and driving to a temporary work location. It generally does not include your regular commute from home to a fixed primary workplace — that is considered personal, even if you are self-employed. Mixed-use vehicles are fine; you simply deduct the business-use percentage rather than the whole vehicle.

Method 1: The Standard Mileage Rate

This method uses a flat rate per business mile driven, set annually by the IRS, that bundles together gas, maintenance, depreciation, insurance, and repairs into a single number.

• Multiply your total business miles for the year by the standard rate to get your deduction.
• Requires only a mileage log — no need to save gas or repair receipts.
• Generally favors owners with lower-cost, fuel-efficient vehicles and high business mileage.
• You must choose this method in the first year you use the vehicle for business if you want the option to switch methods in later years; some restrictions apply if you started with actual expenses.

Method 2: Actual Expenses

This method totals up everything you actually spent operating the vehicle, then applies your business-use percentage.

• Add up gas, oil changes, repairs, tires, insurance, registration fees, lease payments or depreciation, and loan interest (if business-owned).
• Multiply the total by your business-use percentage, calculated as business miles divided by total miles driven for the year.
• Requires more detailed recordkeeping — every receipt and a reliable way to track total versus business mileage.
• Often favors owners with more expensive vehicles, high repair or lease costs, or lower overall mileage where the flat per-mile rate would undervalue the real cost.

How to Decide Which Method Wins

• Run both calculations for your actual numbers before filing — the better method varies year to year and vehicle to vehicle.
• High-mileage, lower-cost vehicles usually favor the standard mileage rate.
• Lower-mileage, higher-cost, or heavily financed vehicles usually favor actual expenses.
• If you plan to claim depreciation or Section 179 on the vehicle, you generally must use actual expenses, since the standard rate already includes a built-in depreciation component.

Recordkeeping That Actually Holds Up

• Keep a contemporaneous mileage log — date, starting and ending odometer readings or miles driven, destination, and business purpose for each trip. Apps that track this automatically make it far easier than reconstructing it later.
• Save all receipts if using the actual expense method, and keep a running total of both business and total annual mileage regardless of method, since the business-use percentage matters either way.
• Note your odometer reading on January 1 and December 31 each year to establish total annual mileage.

Vehicle deductions are one of the more commonly scrutinized categories on a return, not because the deduction itself is unusual, but because recordkeeping is often thin. A simple, consistently maintained mileage log is what separates a deduction that holds up from one that does not — and it takes only a few seconds per trip to keep.