How to rebuild a 2026 mileage log you didn’t keep

What every business drive needs

For a car, the IRS asks you to back up these things for each business drive, plus one for the whole year:

• The date.
• The place: where you drove for business.
• The miles. Noting where you started and ended lets anyone check them on a map.
• The business purpose: who you saw, or what the drive was for.
• The car’s total miles for the year, so your business share can be worked out.

Drives between home and your regular place of work are commuting, and commuting is personal. Leave them out.

This is for people who can deduct car expenses: the self-employed, gig drivers, landlords and others in business for themselves. Most employees can’t deduct miles their employer doesn’t pay back.

Why a rebuilt log needs backup

The tax regulations give a record made at or near the time of a drive a high degree of credibility that a statement written later doesn’t have. Without one, you back up each drive with your own detailed account plus other evidence that corroborates it. For dates and miles, the IRS says that evidence has to be direct or documentary: records, not just your word.

Car expenses fall under section 274(d) of the tax code, which rules out a reasonable estimate on its own. “About 9,000 business miles” won’t hold up without the drives behind it.

Evidence that backs up a drive

• Google Maps Timeline, if it was on: where you went and when.
• Calendar events with an address: showings, appointments, site visits.
• Photos taken on the job, which can hold when and where they were taken.
• Invoices, work orders, client lists and delivery records.
• Trip histories from Uber, Lyft, DoorDash or Instacart.
• Toll and parking statements, and receipts or card statements that show where you were.
• Emails and texts that set up a meeting.
• Service invoices, inspections or photos that show the odometer.

Rebuild it, step by step

1. 1

   Pin down the year’s total miles

   Find the odometer reading closest to January 1, 2026, on an oil change or inspection invoice, and photograph the odometer as close to December 31 as you can. Account for the miles between those readings and the year’s first and last days.

2. 2

   Export your Google Maps Timeline, if it was on

   On an iPhone, in the Google Maps app: tap your picture › Settings › Location & Privacy › Export Timeline data, then Save to Files. On Android: Settings › Location › Location services › Timeline › Export Timeline data. Timeline is kept on your phone, so Google Maps on a computer doesn’t show it. Do it soon: Timeline can be set to delete older history automatically.

3. 3

   Request your trip history

   If you drove for Uber or Lyft, ask for your data. Uber lets you know when your file is ready; Lyft emails you, and says it may take a few days.

4. 4

   Go through your calendar and photos

   Go month by month, noting each work trip.

5. 5

   Write one line per business drive

   Give the date, where you started and ended, the purpose, and the miles, measured on a map rather than guessed.

6. 6

   Say it’s rebuilt

   Note when you made the log and what each drive rests on. Never present it as a log kept at the time.

7. 7

   Keep the evidence with the log

   Keep the Timeline file, trip histories and receipts as long as the return: at least three years from when you file, or from the due date if you file early.

Kept a log for part of the year?

A record kept for part of the year can stand in for the whole year if other evidence, like invoices, shows those periods were typical. The regulations’ own examples are a log for the first three months of the year, and a log for the first week of every month. If your work changed during the year, a sample won’t speak for the rest.

The 2026 rates

The IRS raised its business and medical rates in the middle of the year, so a drive’s date decides its rate.

With the standard rate, gas and repairs are already counted, but parking and tolls for business drives can be added.

Sources

• Treasury Regulation § 1.274-5T: what to substantiate for a car, records made at or near the time, other corroborating evidence, sampling, and lost records
• 26 U.S.C. § 274(d): the substantiation rule for car expenses
• IRS Publication 463, Travel, Gift, and Car Expenses: what to record (Table 5-1), commuting, the standard mileage rate, and how long to keep records
• IRS Standard mileage rates (IR-2025-128 and IR-2026-29)
• Google Maps Help, Manage your Timeline (iPhone; the page also covers Android)

This is general information, not tax advice. Your situation may differ, so ask a tax professional before you file. Google Maps, Uber, Lyft, DoorDash and Instacart are trademarks of their owners; Tenths isn’t affiliated with or endorsed by them.