A mileage log is the written record that proves your vehicle deduction. For every business trip the IRS expects the date, the destination, the business purpose and the miles driven, plus your vehicle’s total miles for the year. It has to be kept at or near the time of the trip. A paper notebook, a spreadsheet or an app all qualify; what matters is that the entries are complete and timely.
What each entry needs
- Date of the trip.
- Destination, or the place you drove to: a client name and town is enough.
- Business purpose, specific enough to make sense a year later. “Meeting” is thin; “Site measure, Ortega bathroom remodel” is solid.
- Miles driven, from odometer readings or a mapped route.
For the year as a whole, record the odometer reading on January 1 and December 31 (or when you start and stop using the vehicle for business). Your deduction depends on business miles as a share of the total, and the totals are what prove it.
An example entry
| Date | From / to | Business purpose | Miles |
|---|---|---|---|
| Aug 4 | Home office to Lakeside Hotel, and back | Wedding venue walkthrough, Kim/Patel | 38 |
| Aug 6 | Home office to camera shop | Lens repair pickup | 12 |
| Aug 8 | Home office to Lakeside Hotel, and back | Wedding shoot, Kim/Patel | 38 |
That week is 88 business miles. Driven after July 1, 2026, they are worth 76 cents each under the standard mileage rate: $66.88. Our free 2026 mileage log template (spreadsheet and printable PDF) has these columns and splits the year at July 1 for you, and the mileage deduction calculator turns a year of miles into a deduction.
Kept at the time
The IRS gives far more weight to a record made at or near the time of the trip than to one rebuilt later from a calendar. Filling in the week’s trips at the end of each week still counts as timely. If your driving is the same week after week, you can keep a full log for a representative part of the year and use it for the rest, as long as you can show that sample is typical. An app that records each drive as it happens, like BrassWell’s GPS trip tracking, makes the timeliness question disappear.
Which miles count
- Count: trips to clients, job sites, suppliers, the bank or post office for the business, and between two workplaces.
- Don’t count: commuting from home to a regular office or workplace, and personal stops on a business trip.
- Home office: if your home is your principal place of business, trips from home to clients and suppliers are business miles.
How long to keep it
Keep the log for at least three years after you file the return it supports, and longer if you depreciate the vehicle instead of using the standard rate. If you change how you deduct the car, see the 2026 mileage rate guide for standard mileage against actual expenses.
Questions, answered
What does the IRS require in a mileage log?
For each business trip: the date, the destination, the business purpose and the miles driven. You also need the vehicle’s total miles for the year, usually from odometer readings on January 1 and December 31.
Can I make a mileage log at the end of the year?
A log reconstructed later carries much less weight than one kept at the time. The IRS treats records made at or near the time, including a weekly catch-up, as timely.
Is a mileage tracking app acceptable to the IRS?
Yes. Any written record works, paper or digital, as long as each trip shows the date, destination, business purpose and miles and was recorded at the time.
Can I deduct the drive from home to work?
Not to a regular office or workplace: that is commuting. If your home is your principal place of business, trips from home to clients or suppliers count as business miles.
Sources
- Publication 463, Travel, Gift, and Car Expenses — IRS. Adequate records, timely kept records, sampling and how long to keep them.
- Standard mileage rates — IRS. The 2026 business rates.
- Topic no. 510, Business use of car — IRS. Standard mileage against actual expenses, and commuting.
