How to Track Business Mileage for Tax Deductions: Logs and IRS Rules

To track business mileage for tax deductions, log every qualifying trip the day you take it with five pieces of information: the date, the destination, the business purpose, your starting and ending odometer readings, and any tolls or parking you paid. Keep that log for at least three years after you file, and use the totals to claim either the standard mileage rate (72.5 cents per mile in 2026) or the actual expense method on your return.¹ The mechanics are simple. What trips people up is doing it consistently and knowing which miles count in the first place.

Which Miles Actually Count

Tracking is wasted effort on miles the IRS won’t allow. The line runs between commuting and business travel: driving from home to your regular workplace is a personal commute and is never deductible, no matter how long the drive.²

What does qualify: travel between two work locations in the same day, trips to visit clients or customers, drives to a business meeting away from your regular office, and transportation to a temporary work location (one where you realistically expect to work for a year or less).² If your expectation about the temporary location changes and you realize you’ll be there longer, those trips stop being deductible from the date your expectation shifts.³

Two situations are worth calling out because they change the math substantially. If you work at two jobs the same day, the drive from the first workplace to the second counts, whether or not the jobs share an employer. And if you have a qualifying home office that serves as your principal place of business, every drive from that home office to a client site or secondary location is deductible business mileage rather than a personal commute.² That home-office rule is one of the most valuable and most overlooked provisions for freelancers and gig workers.

Personal detours during a business trip need to be split out. A lunch stop between two client meetings won’t break the chain, but a trip across town for a personal errand means the personal miles come out of your business total.

What Your Log Has to Show for Every Trip

Federal law requires you to substantiate the amount, time, place, and business purpose of every vehicle expense you deduct.⁴ Publication 463 turns that into a specific list. For each business trip, your log needs:

The calendar date.
The destination (city, town, or area).
A brief business purpose, such as “met with client about kitchen renovation project.”
Starting and ending odometer readings, and the total miles driven.
Any out-of-pocket costs tied to the trip, like tolls or parking.

These come straight from Table 5-2 in Publication 463, which the IRS treats as the model for an acceptable daily mileage log.² You also need to record total miles driven for the whole year, business and personal combined, because the IRS uses that number to compute your business-use percentage. The simplest way to capture it is to write down your odometer on January 1 and December 31.

Log It the Day You Drive It

The regulations require these records to be made “at or near the time of the expenditure or use.”⁵ In plain terms, log each trip the same day. A log reconstructed from memory weeks or months later is exactly the evidence the IRS rejects, and Publication 463 states outright that approximations and estimates are not allowed.²

There is one shortcut. If your driving pattern is consistent throughout the year, Publication 463 lets you keep a detailed log for a representative portion of the year and use it to project your business-use percentage for the rest.² You still need other evidence showing the sample period reflects your typical driving. This fits someone whose business travel follows a predictable weekly routine; it doesn’t fit a rideshare driver whose hours swing with the season.

Paper Log or Mobile App

The IRS doesn’t care whether your records come from a notebook or a smartphone, as long as every required element ends up in the output.

Paper Logbooks

A physical logbook with pre-printed columns for date, destination, purpose, and odometer readings costs a few dollars at any office supply store. It doesn’t need a battery or a signal, and the format guarantees you capture the right fields. The weakness is discipline: it only works if you write in it after every trip. Most people who lose mileage deductions aren’t using the wrong method, they’re using one that makes it easy to skip entries on busy days. If you go with paper, keep the logbook in the vehicle where it’s hard to ignore.

GPS Tracking Apps

Mileage apps use GPS to record the distance, route, and timestamp of each trip automatically, then let you classify it as business or personal with a swipe. Better apps detect when you start driving and log the trip without any input, which solves the “forgot to write it down” problem. Many also generate reports formatted for tax preparation.

The tradeoff is that automatic tracking sometimes picks up personal trips or misclassifies short errands, so review the data weekly and clean it up. Five minutes on a Sunday prevents a scramble in April. If your app doesn’t capture odometer readings, supplement it with beginning-of-year and end-of-year odometer snapshots so you can establish total annual mileage.

What the Log Feeds Into: Standard Rate or Actual Expenses

At tax time you pick one of two methods to convert your mileage records into a deduction. The choice can mean hundreds or thousands of dollars, and the first-year decision limits your options later.

The standard mileage rate is 72.5 cents per mile for 2026, up from 70 cents in 2025.¹ You multiply your business miles by the rate. The rate is designed to cover gas, oil, insurance, repairs, registration, and depreciation in one figure. Tolls and parking are still deductible on top.²

The actual expense method requires you to track every cost of operating the vehicle (fuel, insurance, repairs, maintenance, tires, registration, loan interest, lease payments, depreciation) and multiply the total by your business-use percentage. Drive 15,000 total miles with 10,000 for business and your business-use percentage is 66.7%. The paperwork is heavier because you’re keeping receipts for every oil change on top of the mileage log.

The standard rate tends to win for fuel-efficient or fully paid-off vehicles with low operating costs. Actual expenses tend to win with newer vehicles that carry high depreciation. Run both calculations in year one if you’re unsure.

The First-Year Lock-In

If you own the vehicle and want to use the standard mileage rate, you must elect it in the first year the car is available for business use.⁶ After that first year, you can switch between the two methods in any later year. But if you start with actual expenses and claim accelerated depreciation, a Section 179 deduction, or bonus depreciation on the vehicle, you’re locked out of the standard mileage rate for that vehicle permanently. If you later switch from the standard rate to actual expenses, you must use straight-line depreciation for the vehicle’s remaining useful life.⁷ Starting with the standard rate is the flexible choice.

Leased vehicles are stricter: if you choose the standard mileage rate, you must use it for the entire lease period, including renewals. And the standard rate is not available if you operate five or more vehicles at the same time; fleet operators must use actual expenses.⁶

Where the Numbers Go on Your Return

Sole proprietors and single-member LLC owners report vehicle expenses on Schedule C (Form 1040). Car and truck expenses go on Line 9.⁸ Part IV of Schedule C asks for the supporting detail your log should already contain: total business miles, commuting miles, total other miles, the date the vehicle was placed in service, and whether you have written evidence to support the deduction. Fill out Part IV separately for each vehicle if you used more than one.

W-2 employees generally cannot deduct mileage. The 2017 tax law eliminated miscellaneous itemized deductions through 2025, so the only employees who can still claim unreimbursed vehicle expenses on Form 2106 are Armed Forces reservists, qualified performing artists, fee-basis state or local government officials, and employees with impairment-related work expenses.⁹ If you don’t fall into one of those categories, your route is a mileage reimbursement plan from your employer, not a deduction on your return.

What Weak Records Cost You

If the IRS audits your return and finds your mileage claims aren’t backed by adequate records, the entire deduction gets disallowed, which raises your taxable income and the tax you owe. The IRS can add an accuracy-related penalty of 20% of the resulting underpayment when the underpayment is attributable to negligence, defined by statute to include any failure to make a reasonable attempt to comply with the tax code.¹⁰

Auditors watch for red flags: implausibly high business-use percentages (95% on a vehicle that’s also the family car), round-number totals that suggest estimation rather than tracking, and gaps between claimed mileage and what a vehicle plausibly drove in a year. A contemporaneous log with specific destinations and purposes is the strongest response to any of these questions.

How Long to Keep Everything

Retain mileage logs, app-generated reports, and supporting documents like toll receipts for at least three years from the date you file the return claiming the deduction.¹¹ If you file early, the three-year clock starts on the original due date. Scan paper logs and store digital backups somewhere independent of the original: a water-damaged notebook or a lost phone shouldn’t be the reason you can’t defend a legitimate deduction. If you use a tracking app, export the annual data to a PDF or spreadsheet at year-end so your records don’t depend on the app company staying in business.

1
Internal Revenue Service. IRS Sets 2026 Business Standard Mileage Rate at 72.5 Cents Per Mile, Up 2.5 Cents
2
Internal Revenue Service. Publication 463 – Travel, Gift, and Car Expenses
3
Internal Revenue Service. Topic No. 511, Business Travel Expenses
4
Office of the Law Revision Counsel. 26 U.S. Code 274 – Disallowance of Certain Entertainment, Etc., Expenses
5
eCFR. 26 CFR 1.274-5 – Substantiation Requirements
6
Internal Revenue Service. Topic No. 510, Business Use of Car
7
Internal Revenue Service. Rev. Proc. 2019-46 – Standard Mileage Rates
8
Internal Revenue Service. Instructions for Schedule C (Form 1040)
9
Internal Revenue Service. Instructions for Form 2106
10
Office of the Law Revision Counsel. 26 U.S. Code 6662 – Imposition of Accuracy-Related Penalty on Underpayments
11
Internal Revenue Service. How Long Should I Keep Records