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Mileage records the IRS expects: what to write down and how long to keep it

Updated October 19, 2026. Educational, not tax advice.

IRS Publication 463, chapter 5 (Recordkeeping), sets out what a mileage record should show.

What to record for car use

Publication 463’s Table 5-1, 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; the date of the use; your business destination; and the business purpose.

“At or near the time” — and weekly counts

“You should record the elements of an expense or of a business use at or near the time of the expense or use and support it with sufficient documentary evidence. A timely kept record has more value than a statement prepared later.” Publication 463 also says you don’t need to write it down the same day: “If you maintain a log on a weekly basis that accounts for use during the week, the log is considered a timely kept record.”

What kind of record

An “account book, diary, log, statement of expense, trip sheets, or similar record,” plus documentary evidence such as receipts, canceled checks or bills. Publication 463 says documentary evidence isn’t needed for an expense (other than lodging) under $75, or for a transportation expense where a receipt isn’t readily available — but you still need the written record.

One trip with several stops can be one record: Publication 463 says a round trip or uninterrupted business use can be recorded as a single use, and a lunch stop between two business stops isn’t an interruption.

How long to keep it

“Generally, this means you must keep records that support your deduction … for 3 years from the date you file the income tax return on which the deduction is claimed. A return filed early is considered filed on the due date.”

Sampling

Publication 463 allows an adequate record for part of the year to prove use for the whole year only if you can show the sampled periods are representative. For drivers whose weeks vary a lot, a full-year log is the safer habit.

Want this on paper? The $12 Tax & Mileage Kit has a 2026 rate table and a monthly summary that handle the July 1 rate change, a printable weekly mileage log, a receipt checklist, and questions to bring to your tax pro. Buy it on Gumroad.

IRS sources

Educational, not tax advice. Rules depend on your facts. Confirm with a CPA or enrolled agent and with the IRS sources below.