Mileage log requirements: what the IRS wants to see

A mileage log is a simple record of the business trips you make in your car. For each trip, it shows when you went, where you went, why you went and how far you drove.

If you deduct car costs on your tax return, you need this record. The IRS says you cannot deduct amounts that you approximate or estimate (IRS Publication 463). A car deduction with no log is an estimate.

The short version

• For each business trip, write down the date, the place, the business reason and the miles.
• For the year, write down your total miles, business and personal.
• Write it at or near the time of the trip. A log you update once a week is fine (IRS Publication 463).
• Paper, a spreadsheet or an app all work. What matters is what is in it.
• Schedule C asks if you have evidence for your car deduction, and if that evidence is written (Schedule C).

Words to know

Business miles are miles you drive for your work, such as a trip to a client or to buy supplies. A trip that keeps you away overnight is business travel, with its own rules.

Commuting miles are miles from your home to your regular place of work. They are personal, not business.

Standard mileage rate is a set amount per business mile that you can deduct instead of your real car costs. For 2026 it is 72.5 cents a mile from January 1 to June 30, and 76 cents a mile from July 1 to December 31 (IRS).

What to write for each trip

Publication 463 lists what you must be able to prove. For each business trip, record:

• the date,
• the place you went (a client name and town is enough),
• the business reason, and
• the miles.

Make the reason clear. “Meeting” tells nobody anything. “Meeting with Bright Dental about new website” can be checked.

For the whole year, record your odometer reading at the start and end of the year. The difference is your total miles. Also note the date you started to use the car for business.

How often to write it down

The IRS says to record each trip at or near the time. You do not have to write in the log every day. A log you keep each week, that accounts for the use in that week, counts as a timely record (IRS Publication 463). Ten minutes on a Friday afternoon is enough for most people. Overnight trips have more rules; see business travel deductions.

A record on a computer is also an adequate record. So a spreadsheet or a phone app is fine.

Shortcuts the IRS allows

A regular route. If you drive the same delivery route again and again, you can record the length of the route once, the date of each trip, and your total miles for the year.

Sampling. You can keep a full log for part of the year, such as the first week of each month, and use it for the whole year. This works only if that part is typical of your driving all year.

An example

Dana is a freelance interior designer. (She is an example, not a real person.) Her home office is her main place of business, so trips from home to clients count. One week of her log looks like this:

Her odometer read 41,220 on January 1, 2026 and 55,870 on December 31. Her total miles for the year are 14,650.

These trips are after July 1, so they use the 76 cent rate. 81 × $0.76 = $61.56 for the week. The dates in her log split her miles between the two 2026 rates.

Receipts, gaps and how long to keep it

If you use the standard rate, you do not need gas receipts, because the rate covers gas. Keep records of parking and tolls, which you deduct as well. See do I need to keep receipts for the general rules.

If your log has gaps, fill them now. Use your calendar, invoices, emails and card charges. Mark these trips as rebuilt. If your records are incomplete, Publication 463 says you must prove the missing part with your own statement plus other evidence.

Generally, keep records that support a deduction for 3 years from the date you file the return (IRS Publication 463). See how long to keep business records.

A tip for Righto users

Righto does not track mileage. But your books help you rebuild a log with gaps, because each dated fuel, parking and toll charge shows where you were. In Righto, you can ask your own AI agent, such as Claude Code, to list your parking and fuel charges for the months you missed. See how agents work with Righto. When your log is done, the mileage deduction calculator applies both 2026 rates.

Common questions

Do I need to log personal trips? No. Log business trips and your total miles for the year. Personal miles are the difference. Schedule C also asks for commuting miles, so note those too.

Does phone location history count as a log? It helps you rebuild trips, but it does not show the business reason. Add that yourself.

Do I need a separate log for each car? Yes. Keep the odometer readings and business miles for each car apart.

What to do now

1. Write down today’s date and your odometer reading.
2. Fill any gaps in your 2026 log from your calendar and invoices.
3. Pick one time each week to update the log.
4. Enter the car deduction on Schedule C when you file.

Righto is free, easy to use and needs no account.

Sources

• Publication 463, Travel, Gift, and Car Expenses, IRS (chapter 5, Recordkeeping)
• Standard mileage rates, IRS
• Schedule C (Form 1040), Profit or Loss From Business, IRS