What does the IRS want to see in a mileage log?

What a log has to show

IRS Publication 463 asks for a record of each business drive that shows four things: the date, the miles, the destination and the business purpose. For the car itself it asks for the total miles for the year, the date it started being used for business, and what the car and any improvements cost. It says timely and accurate records are the support to show the IRS if a return is ever examined, and that amounts that are approximated or estimated cannot be deducted. What the IRS actually wants in a mileage log goes through each rule and where it comes from.

A log from an app, or kept by hand

Publication 463 does not name one kind of log. It lists an account book, diary, log, statement of expense, trip sheets or a similar record, says a record generally has to be written, and says a record prepared on a computer is considered an adequate record. What it weighs is when a record was made: one made at or near the time of the drive has more value than a statement prepared later, and a log kept weekly counts as timely kept.

In OdoTax a drive you add by hand is in the same log as the recorded ones, and a report says which is which: the PDF marks it with an asterisk (*), its last page says how many drives were recorded as they happened and how many were entered by hand, and the CSV has a How logged column. A drive Claude added for you, or one imported from Google Maps Timeline, has a mark of its own. To add a drive OdoTax missed: How do I add a drive by hand?. If you kept no log: I didn’t keep a mileage log. What can I do?.

What OdoTax fills in, and what you add

For each drive it records, OdoTax keeps the date and time, where the drive started and ended, and the miles. The rest is yours to add:

1. The type and the purpose — whether the drive was Business, and what it was for. A business drive with no purpose shows Not recorded in the report: How does OdoTax know which drives are for work?
2. Odometer readings — one near the start of the year and one near the end pin down the car’s total miles: Should I add odometer readings?
3. The date the car went into business use — In business use since, on the car’s page under Settings → Vehicles in the web account

OdoTax does not keep what the car cost. Parking and tolls are recorded as amounts, not receipts, so keep the receipts yourself.

What the report holds

The report’s PDF has a trip log, one row a drive: date, time, type, business purpose, where it started, the destination, miles, rate, parking and tolls, and what it is worth. Its first page has a table of your vehicles with the date each went into service, its odometer at the start and end of the period, and its business, commute and other miles: the figures Schedule C Part IV asks for. What you have not entered prints as a dash. Drives still waiting to be sorted, and drives locked by the free plan’s monthly limit, are not counted; the report says how many.

What does the report contain? goes through each page, and How do I export a log for my taxes? shows how to make one.