How to keep a mileage log for taxes

Why the log matters

Business-mile deductions are only worth something if you can back them up. The IRS standard mileage rate changes every year, so check the current rate on irs.gov rather than relying on a number you saw somewhere else. What doesn't change is the requirement: a contemporaneous record beats a reconstructed one every time.

What a mileage log must record

At minimum, each trip needs a date, a start and end location, the distance driven, and the business purpose. Missing any one of these turns a clean deduction into a guess.

Three ways to keep one

Paper notebook— free, and it works, but only if you remember to write in it after every single drive. Most people don't.

Spreadsheet— more flexible, easy to total up at month's end, but still manual entry for every trip. It survives exactly as long as the habit does.

Automatic app — captures the drive without you doing anything, which solves the forgetting problem. The trade-off moves elsewhere: now you need a way to sort business drives from personal ones without reviewing every trip by hand.

The classification problem nobody mentions

Capturing drives automatically is the easy part — most apps do that now. The part that actually determines whether you keep the log going is what happens next: sorting each trip into business or personal. Left unclassified, drives pile up into a backlog that gets skipped at tax time, which is the same outcome as never logging them at all.

What to hand your accountant at tax time

A clean export — one row per trip, with the date, distance, classification, and the reason for that classification — is enough for most accountants to work from directly. A CSV file opens in anything they already use.

This is general information, not tax advice. Consult a qualified professional for your specific filing decisions.

Related: Business miles vs. personal miles: what actually counts. Back to MileClerk.