What an IRS Mileage Log Should Record

This guide focuses on US federal recordkeeping for people who use a personal vehicle for business, especially self-employed people. Employees may need similar trip details for reimbursement, but their employer’s policy and the tax treatment of unreimbursed expenses are separate questions.

What belongs in a mileage log?

The IRS’s Publication 463 describes the records used to substantiate car expenses. For transportation, its table calls for the date of each use, business destination, business purpose, mileage for each business use, and total miles for the year. In practice, a useful trip record includes:

• Date of the trip.
• Destination or area visited.
• A short business purpose, such as “client meeting” or “pick up materials for Job 184.”
• Business miles for that trip.
• Vehicle identification, so the trip can be matched to the right car.
• Odometer readings or other year-total records that support total annual mileage and the vehicle’s business-use share.

For reimbursement, your employer may also request the start and end locations, project or client name, route, or odometer readings. Follow that policy even if your tax record has a different layout.

Here is a fictional example. It demonstrates a useful level of detail, not an IRS-approved form or a record for an actual taxpayer:

If you use the standard mileage rate, parking fees and tolls related to business travel may be treated separately under IRS rules. Save receipts or other records for those costs when needed. A mileage total alone does not document every vehicle expense.

Record trips while the details are fresh

The IRS says records made at or near the time of the trip generally have more value than a statement prepared later from memory. A log kept weekly can count as timely if it accounts for that week’s use. Build a routine that makes the purpose and destination easy to add before details fade; do not assume a location trace will explain why a trip was business-related.

Keep supporting records that help substantiate the trip, such as client appointments, invoices, delivery records, calendars, or work orders. They can provide context if a short trip note needs explanation. Protect client or patient information: record only what you need, and store sensitive details separately when appropriate.

Keep business and personal driving distinct

If a vehicle is used for both work and personal travel, separate those miles. The business portion of vehicle costs depends on business use, and commuting is generally personal. Read IRS Publication 463’s commuting rules before counting travel between home and a regular workplace; special circumstances can change the analysis.

For a tax-year checklist, reconcile trip entries against odometer readings at the beginning and end of the year, check for missing dates or purposes, and total business and overall miles. If you want to see what a mileage record can look like when exported, view the fictional FlatMile sample report. It shows FlatMile’s output layout; it is not approved or certified by the IRS and is not a guarantee that a taxpayer’s records will be accepted.

Does an app make a log IRS-compliant?

No app can promise acceptance simply because it tracks a route or labels a report “tax-ready.” You remain responsible for reviewing the trips, correcting mistakes, documenting business purpose, and keeping records that support your return. Automatic location capture can help create a starting record, but it may miss or split drives and cannot know the business reason by itself.

FlatMile offers free automatic and manual drive logging. A subscription or eligible trial unlocks captured-drive details, business/personal classification, and PDF and CSV exports. Drivers should review and correct their entries. For a blank file, start with the free mileage log template.

Related guides

• Commuting Miles vs. Business Miles: What Counts?
• How Long Should You Keep Mileage Logs?
• How to prepare a mileage report for your accountant
• How to Write a Useful Business Purpose in a Mileage Log
• How to Recover a Missing Mileage Log Without Inventing Trips
• What an “IRS-approved mileage app” claim should make you check

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