IRS Mileage Log Requirements: What Your Records Must Show
To deduct business miles you don't send the IRS your log — you keep it, and produce it if you're ever asked. That means it has to be complete and believable. Here's what a log actually needs to contain.
The records the IRS expects
For the standard mileage method the IRS wants records that establish the business use of your vehicle. In practice, each business trip should show four things:
Required per-trip records
| Field | Why the IRS wants it |
|---|---|
| Date of the trip | Ties the mileage to the tax year and proves it isn't back-filled in bulk. |
| Miles driven | The number your deduction is calculated from. |
| Business purpose | Shows the trip was for work, not personal use — e.g. 'client visit', 'delivery run'. |
| Where you went | Start/end or destination corroborates the purpose and distance. |
You should also be able to show your total miles for the year (business + personal), so the business share is credible. Milvo keeps both the per-trip detail and the running totals, and its export lays out date, distance, purpose and route in the order above.
The single most common reason a log fails: it was written from memory months later. The IRS expects records kept at or near the time of each trip — 'contemporaneous'. A log reconstructed in one sitting the week before you file is the weakest kind of evidence.
What makes a log hold up
How to keep an audit-proof mileage log
- Record every business trip close to when it happens — not in a year-end catch-up.
- Note the purpose in a few words while you still remember it ('showing on Elm St', 'supply pickup').
- Separate business from personal so the business percentage is clear.
- Keep the log for at least three years after you file — the standard IRS look-back window.
- Store it somewhere it won't be lost if your phone is — export a copy each quarter.
Milvo is built around the first three: drives are captured in the background as they happen, a swipe marks each one business or personal, and anything unsorted waits in a review queue so nothing is quietly forgotten. When you need the record, one export produces a PDF and CSV with the fields above.
Frequently asked questions
Does the IRS require a specific mileage log format?
No official form is mandated — what matters is that the records show the date, miles, business purpose and destination, and that they were kept close to the time of each trip. A clean PDF or spreadsheet with those columns is fine.
How long do I need to keep my mileage log?
Keep it at least three years from the date you file, which is the usual IRS audit window. Some situations extend it further, so many drivers keep logs for six or seven years to be safe.
Can I use an app instead of a paper logbook?
Yes. A timestamped digital log is generally stronger than a handwritten one because the dates and distances aren't easily altered after the fact. The requirement is about content and timeliness, not paper.
What if I forgot to log some trips?
Add them as soon as you remember, with the real date and purpose — don't invent round numbers. A log with a few honest manual additions is fine; a log fabricated wholesale at year-end is the problem. Milvo's two-tap manual add is there for exactly this.