Updated November 7, 2026. Quick answer: A mileage log has to show, for each business use of the car, the date, the business destination, the business purpose and the miles, plus the total miles driven for the year. Publication 463 lists those items in its recordkeeping table, and the regulation says a contemporaneous log is not required, only a record made at or near the time. A log kept on a computer or a phone counts the same as paper. Commuting miles never count, whatever you do on the drive.
On deductions by profession: tax deductions for musicians and performers, tax deductions for notaries and signing agents and tax deductions for interior designers.
On deductions by profession: tax deductions for real estate agents.
On records for a one-person business: vehicle expenses under the actual method and rebuilding a lost receipt.
What the log has to show
This page reads the primary sources linked under Sources, as retrieved on November 6 and 7, 2026. Publication 463 is the 2025 edition.
Section 280F(d)(4) of the Internal Revenue Code puts a car in the category of listed property: “any other property used as a means of transportation” is on the list, together with any passenger automobile. Section 274(d) then requires adequate records of the amount, the time and place, and the business purpose. Publication 463’s recordkeeping table turns that into a car line: “For car expenses, the cost of the car and any improvements, the date you started using it for business, the mileage for each business use, and the total miles for the year.” It adds the date of each use and “Your business destination.” and the business purpose.
| Element | What to record | Where it can come from |
|---|---|---|
| Date | The date of each business trip | Calendar entry or app trip date |
| Destination | The business destination, by name of place or client | Client name or address |
| Business purpose | One line on why the trip was made | Project or meeting name |
| Miles | Miles for the business use, and total miles for the year | Odometer reading at the start and end of the year |
| Vehicle | Cost of the car and improvements, and the date you started using it for business | Purchase paperwork |
Contemporaneous, or just timely?
The regulation is more forgiving than the word “log” suggests: “A contemporaneous log is not required, but a record of the elements of an expenditure or of a business use of listed property made at or near the time of the expenditure or use, supported by sufficient documentary evidence, has a high degree of credibility not present with respect to a statement prepared subsequent thereto when generally there is a lack of accurate recall.” Publication 463 puts the practical line this way: “If you maintain a log on a weekly basis that accounts for use during the week, the log is considered a timely kept record.” A weekly entry from your calendar is therefore enough; a log rebuilt at filing time from memory is the weak version.
Paper, spreadsheet or app
Publication 463 says what counts as a record: “You should keep the proof you need in an account book, diary, log, statement of expense, trip sheets, or similar record.” On format it adds “However, if you prepare a record on a computer, it is considered an adequate record.” A notebook in the glove box, a spreadsheet and a phone app that records trips by GPS all meet the same test, which is whether the elements above are present and were written down at or near the time. A cheap paper log you actually fill in beats an app you stop opening.
The shortcut that is allowed: sampling
You do not have to log every trip all year if you can show a representative period. The regulation allows it for listed property: “a taxpayer may maintain an adequate record for portions of a taxable year and use that record to substantiate the business/investment use of listed property for all or a portion of the taxable year if the taxpayer can demonstrate by other evidence that the periods for which an adequate record is maintained are representative of the use for the taxable year or a portion thereof.” The regulation’s own example is a sole proprietor who logs the first three months and shows with invoices that business continued at the same rate. The condition is the other evidence, so keep the invoices or calendar that show the rest of the year looked like the logged weeks. Publication 463 also describes a fixed delivery route: “You can satisfy the requirements by recording the length of the delivery route once, the date of each trip at or near the time of the trips, and the total miles you drove the car during the tax year.”
What never counts
Driving from home to a regular place of work is commuting. Publication 463 is blunt about a common mistake: “You can’t deduct commuting expenses even if you work during the commuting trip.” Its example is taking business calls during the drive. Log trips between work locations and to clients, not the daily trip to a regular workplace. If your home is your principal place of business, trips from home to another work location are the ones that count; see Schedule C line 9, car and truck expenses and the 2026 standard mileage rate.
How long to keep it
Keep the log with the year’s other records. The IRS default is: “Keep records for 3 years if situations (4), (5), and (6) below do not apply to you.” The listed situations can lengthen it; see Bookkeeping for a One-Person Business.
A phone app is one option
SparkReceipt’s pricing page lists “Mileage tracking and expense reports” among the Pro plan’s features, and its home page says the phone app can log a trip by GPS. Both statements are the vendor’s own; this page has not used the product. Whatever tool you use, the test is the table above, and the spreadsheet and paper routes remain complete alternatives.
Common mistakes
- Recording miles with no purpose or destination. Miles alone leave two of the required elements empty.
- Rebuilding the year from memory in March. The regulation treats a record made later as needing much stronger backup.
- Logging commuting trips, or leaving out the year’s total miles. The total is part of the record, and it is what the business percentage is divided by.
- Starting the log in the spring and assuming the early months need none. Sampling only works if you can show the logged weeks were representative.
Related: the 2026 standard mileage rate, Schedule C lines 8 and 9, and Receipts and Expense Records for a One-Person Business.
Sources
- IRS Publication 463 (2025), Travel, Gift, and Car Expenses
- Treas. Reg. 1.274-5T, Substantiation requirements (temporary) (Cornell LII, eCFR text)
- 26 U.S.C. 274, Disallowance of certain entertainment, etc., expenses (Cornell LII)
- 26 U.S.C. 280F, Limitation on depreciation for luxury automobiles; limitation where certain property used for personal purposes (Cornell LII)
- IRS, How long should I keep records
Read from the IRS documents linked above on November 7, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer, the account provider or the IRS is the right place to confirm anything consequential.