Mileage log and trip log requirements

This page is general information, not tax advice.

A mileage log, trip log, and mileage record are the same thing to the IRS. To deduct the business use of your car, you must be able to prove the miles you drove for business, and Publication 463 lists the elements the record must show. It also says a record kept at or near the time of the driving is worth more than one written up later. The rules are in chapter 5 of Publication 463.

The elements

Table 5-1 in Publication 463 lists what your records must show for car expenses.

If you use the standard mileage rate, the amount column is the miles times the rate for that period. If you use actual expenses, it is the cost of each expense, and the business-use percentage comes from the business miles divided by the total miles for the year.

The total miles for the year is the element most people miss. It needs an odometer reading at the start and end of the year. Without it, you cannot show what share of your driving was business.

Timely kept records

Publication 463 says you should record the elements of a business use at or near the time of the use. You do not have to write down every trip on the day you take it. A log you maintain weekly counts as a timely kept record, as long as it accounts for the use during that week. An automatic mileage log that records each drive as it happens is the strongest form of the same thing.

The reason is evidence. A record made when the trip happened has more value than a statement prepared later, when there is usually a lack of accurate recall.

Business purpose

You must generally provide a written statement of the business purpose. The degree of proof depends on the circumstances. If the purpose is clear from the surrounding facts, you do not need a written explanation. Publication 463 gives the example of a sales representative on an established route, who can record the route once, the date of each trip at or near the time of the trips, and the total miles for the year.

You do not have to put confidential information such as a client's name in the log itself, as long as you record it elsewhere at or near the time and can produce it if asked.

When several stops are one record

You can account for several uses of your car that are part of a single use, such as a round trip or an uninterrupted business route, with a single record. A minimal personal stop, such as lunch between two business stops, does not interrupt the business use.

The publication's own example is deliveries. If you make deliveries at several locations on a route that begins and ends at your business premises, you can account for the route with a single record of the miles driven.

Commuting vs. business miles

Driving between your home and your regular place of work is commuting, and commuting is a personal expense. It is not deductible no matter how far you live from work. Publication 463 chapter 4 summarizes the rules in Figure B.

A temporary work location is one where the work is realistically expected to last one year or less, and does. If you have a regular workplace elsewhere, the round trip between home and a temporary location is deductible regardless of distance.

If your home office qualifies as your principal place of business under Publication 587, trips from home to another work location in the same business are business transportation. This is the rule that turns a self-employed person's first and last drive of the day into business miles. If you have no regular office and no home office, the first business contact of the day is treated as your office, so the drive to it and the drive home from the last one are commuting, and the drives between contacts are business.

Hauling tools, advertising on the car, or a nonprofit car pool do not turn a commute into business driving. Parking at your regular workplace is a commuting expense, while parking at a client's office is business.

Missed or incomplete records

Publication 463 says you cannot deduct amounts you approximate or estimate, and it sets out what to do when records are incomplete. To prove an element without a complete record, you need your own written or oral statement with specific information about the element, plus other evidence sufficient to establish it. For the date, place, and mileage of a trip, the other evidence must be direct or documentary, such as a calendar entry, an invoice, a delivery record, a parking or fuel receipt, or a service invoice with an odometer reading. For the business purpose, circumstantial evidence is enough, and the nature of your work, such as making deliveries, counts.

Each of those records gives a date and a place. The miles between two places can be computed from a map, which is a reconstruction of a specific trip rather than an estimate of a total. Do not write a round number of business miles on the return, and do not backdate a log. A reconstructed log should say when it was made.

Sampling is also allowed. An adequate record for part of the year can prove business use for the whole year if other evidence shows the sampled periods are representative. The example is a log kept for the first week of each month, supported by invoices showing the same pattern in the other weeks.

Retention

Keep the log for three years from the date you file, and for every year of the car's recovery period if you depreciate it. The details are on mileage and taxes.

How Miles handles this

Every drive Miles detects is stored with the date, the start and end times, the start and end address and place name, the distance, the route, the purpose, a business-purpose note, and the time the record was created and last edited. The created-at time is the evidence that the record was made at or near the time of the drive. Odometer reminders at the start and end of the year capture the total miles. Shift mode combines a delivery route into a single record, the way chapter 5 allows. A weekly reminder to classify unclassified drives keeps the log within the weekly rule. Private notes stay out of exports, so confidential details can stay off the page you hand to an examiner.

Places tagged Home, Regular workplace, Temporary work location, or a named client drive the commuting rules. A Home office toggle marks the home as the principal place of business, which makes drives from home to a work location business. For a drive the app was not running for, Add drive takes a date and two addresses and computes the distance with Apple Maps directions, and the record shows when it was added.

Miles is coming soon. Until then, the mileage tracker spreadsheet has the same columns.

The Canadian equivalent of these rules is in CRA logbook requirements.