How to Track Mileage for Taxes in 2026

Keep a log of every business trip with the date, destination, purpose, and miles. That is what the IRS requires. Record trips as they happen, not from memory at year-end. Miss this step and your mileage deduction is at risk, no matter how many miles you actually drove.

Source: IRS Publication 463, Chapter 5, Recordkeeping

What the IRS Requires in a Mileage Log

IRS Publication 463 defines "adequate records" for vehicle expenses. Your log needs four data points for every business trip:

1. Date. The specific date of the trip. Not "the week of March 10" or "sometime in March." The date.

2. Destination. Where you went. "ABC Corp, 400 Main St" or "downtown client offices" both work. "Various" does not.

3. Business purpose. Why the trip was business-related. "Client meeting," "delivery route," "supply pickup," "property showing." One or two words is enough. The IRS does not need a narrative.

4. Miles driven. The distance of the trip. Odometer start and end readings, GPS distance, or app-recorded mileage all satisfy this.

In addition to per-trip records, you need:

Odometer reading at the start of the tax year (January 1 or the date you first used the vehicle for business).
Odometer reading at the end of the tax year (December 31).

These readings establish your total miles for the year, which the IRS uses to verify your business-use percentage. If you claim 80% business use but your odometer shows only 10,000 total miles and your log shows 12,000 business miles, you have a problem.

The Contemporaneous Rule

This is where most people get caught. The IRS requires that records be made "at or near the time" of the trip. A mileage log filled out in April from memory does not meet this standard.

"At or near the time" means within a few days. If you record trips weekly, that is generally acceptable. If you wait until month-end, you are in a gray area. If you reconstruct your log at tax time, the IRS considers it unreliable and can reject your entire deduction.

This is the single strongest argument for using an app. An app that runs in the background records every trip automatically, with GPS-verified distance and timestamps. There is no memory involved. If you prefer a manual method, set a recurring daily or weekly reminder to update your log.

Three Ways to Track Your Mileage

Method 1: Paper Logbook

A small notebook in your car. Write down each trip when you complete it. This is the oldest method and it works, if you actually do it every time.

Advantages: No technology needed. No battery drain. No subscription. Auditors accept it.

Disadvantages: Easy to forget. Easy to lose. No backup if the notebook is destroyed. You have to calculate distances yourself (or note odometer readings). Totaling miles at year-end is tedious. Most people start strong in January and stop by March.

Best for: Drivers with a small number of predictable business trips per week who want zero technology involvement.

Method 2: Spreadsheet

A Google Sheet or Excel file with columns for date, destination, purpose, miles, and odometer readings. Some people use a template; others build their own.

Advantages: Automatic math. Backed up to the cloud. Easy to sort and filter. Produces a clean report for your tax preparer.

Disadvantages: You still have to enter every trip manually. Requires discipline. Easy to fall behind. No automatic distance calculation, you need to know the mileage for each trip.

Best for: Drivers who are comfortable with spreadsheets and have a moderate number of business trips. Works well as a weekly data entry habit.

Method 3: Mileage Tracking App

A smartphone app that detects when you are driving, records the trip automatically, and logs the date, route, distance, and start/end locations. You classify the trip as business or personal after the fact (or the app classifies it for you).

Advantages: Automatic. GPS-verified distances. Timestamps that satisfy the contemporaneous requirement without any effort. Year-end reports generated instantly. Nothing to forget.

Disadvantages: Monthly or annual subscription cost for most apps. Uses battery and background location. Requires a smartphone. Some apps have a learning curve.

Best for: Anyone who drives for business regularly. Particularly valuable for gig workers and contractors with dozens of trips per week, where manual logging is impractical.

What Counts as a Business Trip

The tracking method only matters if you are tracking the right trips. Quick reference:

Business (deductible): Trips between your office and a client. Trips between two work locations. Trips to a temporary work site (less than one year). Trips from a qualifying home office to any work location. Errands for business, bank, post office, supply store.

Commuting (never deductible): Home to your regular place of business. Back home at the end of the day. This applies even if you make business calls during the drive or carry tools in your car.

Mixed trips: If you drive from a client meeting to the grocery store, only the portion of the trip related to business is deductible. In practice, most people track the leg from the client to the point where personal driving begins.

For the full rules on what counts, see business vs commuting miles.

How Long to Keep Your Records

Keep your mileage log and supporting documents for at least three years from the date you file your tax return. If you file on April 15, 2027 for tax year 2026, keep records until at least April 15, 2030.

If you underreport income by more than 25%, the IRS has six years to audit. If you file a fraudulent return or do not file at all, there is no time limit. In practice: keep mileage records for at least three years, and consider keeping them for six if you want extra protection.

Digital records (app exports, spreadsheets, photos of logbooks) are accepted by the IRS and easier to store long-term than paper.

What Happens If You Have No Records

If you are audited and cannot produce a mileage log, the IRS can disallow your entire vehicle expense deduction. That includes any amount you claimed on Schedule C, Line 9.

In some cases, the IRS allows a reduced deduction based on whatever partial evidence you can provide, calendar entries, client invoices with addresses, credit card receipts from gas stations near client sites. But this is an uphill argument and the outcome is unpredictable.

The cost of losing a mileage deduction in an audit is real. If you claimed $10,000 in vehicle expenses and the IRS disallows all of it, you owe tax on that $10,000 plus interest and potentially a 20% accuracy penalty. For a self-employed worker in the 22% bracket, that is roughly $3,700 in additional tax, interest, and penalties.

The prevention is cheap: keep a log.

Tips for Better Mileage Records

Photograph your odometer on January 1 and December 31. A timestamped photo is hard to dispute. Store it in your tax folder for the year.

Classify trips immediately. If you use an app, review and classify trips daily or weekly. The longer you wait, the harder it is to remember whether a trip was business or personal. An unclassified trip is a wasted trip at tax time.

Keep a separate folder for parking and toll receipts. These are deductible on top of the standard mileage rate but only if you have documentation. A phone photo of each receipt is sufficient.

Back up your data. If you use a paper logbook, photograph each page weekly. If you use a spreadsheet, keep it in cloud storage. If you use an app, export your data at least quarterly. A lost phone or crashed hard drive should not cost you your deduction.

FAQ

Does the IRS accept app-based mileage logs?

Yes. The IRS accepts electronic records as long as they contain the required information (date, destination, purpose, miles) and are recorded at or near the time of the trip. GPS-based app logs typically exceed the IRS standard for adequate records.

Can I use Google Maps history as a mileage log?

Google Maps Timeline shows your location history, but it does not record business purpose, which is a required element. You could use it as supporting evidence alongside another log, but it is not sufficient on its own.

What if I forgot to track some trips earlier in the year?

You can reconstruct records using supporting evidence, calendar entries, client emails, invoices, and credit card statements that show where you were. This is not ideal (the IRS prefers contemporaneous records), but partial documentation is better than none. Going forward, set up a tracking system so you do not fall behind again.

Do I need to track personal miles too?

Not individually, but you need your total miles for the year (from odometer readings). The IRS calculates your business-use percentage as business miles divided by total miles. If your log shows 12,000 business miles and your odometer shows 18,000 total, your business use is 66.7%. You do not need a log entry for each personal trip.

How often should I update my mileage log?

Daily is best. Weekly is acceptable. Monthly is risky. An automatic app removes the question entirely, every trip is logged the moment it happens.

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