Mileage deduction records: the log and documents the IRS expects

The standard mileage rate is a flat amount per mile that the IRS sets in place of your actual car costs. For the 2025 tax year, the return you file in 2026, the business rate is 70 cents a mile (IRS mileage rates). For the 2026 tax year, the return you file in 2027, there are two business rates: 72.5 cents from January 1 to June 30 and 76 cents from July 1 to December 31 (IRS mileage rates).

That mid-year change is what trips up a 2026 log. A single yearly total cannot be priced, because each half of the year runs at its own rate. So add the business miles twice, once through June 30 and once from July 1, and price each total at its own rate (IRS mileage rates).

Here is how the split works on paper. Say a log shows 4,000 business miles from January to June 2026 and 3,000 from July to December (IRS mileage rates). The first total is priced at 72.5 cents and the second at 76 cents, so the two lines come to $2,900 and $2,280 (IRS mileage rates).

A trip log is the running record of each drive you make for work. The IRS wants proof in a log, diary, trip sheet or similar record, backed by documents for each part of the expense (IRS Publication 463 (2025)). You cannot deduct miles you estimate or guess (IRS Publication 463 (2025)). A record made at or near the time of the trip carries more weight than one rebuilt months later.

For each trip, write the date, where you started, where you went, why, and the miles. For example, a line might read “office to Smith job site, roof estimate,” with the date and the miles. Record the odometer reading at the start and the end of the year too. Total miles against business miles give the business share of the car.

A full log for every week is the safe route, but the IRS also accepts a sample in some cases. Publication 463 gives the example of a business owner who logs the first week of each month, when invoices show the rest of the month follows the same pattern (IRS Publication 463 (2025)). An app works as well, as long as you can export the log as a file you keep with the return.

In IRS terms, commuting is the daily drive between your home and your regular place of business, and it is a personal cost (IRS Publication 463 (2025)). Drives from one work site to another count, such as a run from a client’s office to a supplier. A drive from home to a temporary work location counts if you also have a regular work location; without one, only temporary sites outside your metro area count (IRS Publication 463 (2025)).

A home office changes the starting point. If the office qualifies as your principal place of business, the drive from home to another work location in the same business is deductible (IRS Publication 463 (2025)). The home office records page explains how that test is met and what proves it.

An employee is in a different spot. Unreimbursed job costs are miscellaneous itemized deductions, which the law disallows for every tax year after 2017 (26 U.S.C. 67). Only four groups can still file Form 2106 for job miles: Armed Forces reservists, qualified performing artists, fee-basis state or local officials, and employees with impairment-related work costs (Form 2106 instructions). Other W-2 workers should ask the employer for a reimbursement instead.

Medical and charity miles are personal deductions taken on Schedule A. Medical miles help only if you itemize, and only the part of medical costs above 7.5% of adjusted gross income counts (IRS Publication 502). Charity miles need the name of the group you drove for and the dates.

To use the standard rate for a car you own, you must choose it in the first year the car is available for use in your business; after that, you can switch between methods (IRS Publication 463 (2025)). For a leased car, the standard rate must run for the entire lease (IRS Publication 463 (2025)). If you own or lease five or more cars used for business at the same time, the standard rate is not available for any of them (IRS Publication 463 (2025)).

Some costs come on top of the rate. Business parking fees and tolls are deductible in addition to the standard mileage rate, but parking at your regular workplace is a commuting cost (IRS Publication 463 (2025)). A self-employed owner can also deduct the business share of car loan interest on Schedule C; at 60% business use, that is 60% of the interest (IRS Publication 463 (2025)).

The actual cost method needs every bill: gas, oil, tires, repairs, insurance, registration, lease payments, and the purchase papers for depreciation. It also needs the same log, since only the business share of those costs counts. A car that switches from the standard rate to actual costs must use straight-line depreciation from then on (IRS Publication 463 (2025)).

A separate deduction covers cars bought for personal use. For 2025 through 2028, you may deduct up to $10,000 a year of interest on a qualified vehicle loan, phased out above $100,000 of modified AGI, or $200,000 joint (IRS, 2025 law deductions for individuals). The loan must have been taken out after December 31, 2024, for a new vehicle whose final assembly took place in the United States, and lease payments do not qualify (IRS, 2025 law deductions for individuals).

The paper trail is short but strict. Keep the purchase contract, the lender’s statement of interest paid, and the vehicle identification number, which must go on the return for each year you claim the deduction (IRS, 2025 law deductions for individuals). A self-employed owner who could claim the same interest as a business cost picks one place for it, Schedule 1-A or Schedule C, and never both (IRS Publication 463 (2025)).

• IRS mileage rates: 2025: 70 cents business, 21 medical, 14 charity. 2026: 72.5 cents (Jan. 1 to June 30) and 76 cents (July 1 to Dec. 31) business, 20.5 then 23.5 medical, 14 charity.
• IRS Publication 463 (2025): Adequate and timely records and sampling, commuting and temporary work locations, the first-year choice of the standard rate, leased cars, five or more cars, parking and tolls, and business car loan interest.
• 26 U.S.C. 67: No miscellaneous itemized deduction is allowed for any taxable year beginning after December 31, 2017.
• Form 2106 instructions: Form 2106 may be used only by Armed Forces reservists, qualified performing artists, fee-basis officials and employees with impairment-related work expenses.
• IRS Publication 502: Medical and dental expenses are deductible on Schedule A only above 7.5% of adjusted gross income.
• IRS, 2025 law deductions for individuals: For 2025 through 2028, interest on a loan originated after 2024 for a new, US-assembled personal-use vehicle is deductible up to $10,000, phased out above $100,000 ($200,000 joint); the VIN goes on the return.