How to Record Mileage for Work: IRS Log Rules and Deductions

To record mileage for work in a way the IRS will accept, log four things for every business trip at or near the time you drive: the date, the destination, the business purpose, and the miles driven.¹ Keep a separate running total of business, commuting, and personal miles for the year, and hold the log for at least three years after you file. A log built this way supports a mileage deduction on your tax return or a tax-free reimbursement from your employer; a log reconstructed from memory at tax time usually doesn’t survive an audit.

The Four Things Every Trip Entry Needs

The IRS treats vehicle expenses as one of the categories that requires specific, written substantiation. Each business trip in your log needs all four of the following:

Date of the trip.
Destination, named specifically. “Client meeting” is not enough; “Acme Corp office, 450 Main St” is.¹
Business purpose, in a short phrase like “delivered project proposal” or “met with client to review contract.”¹
Miles driven. Odometer readings at the start and end of the trip are the most reliable way to capture this.

Alongside the trip-by-trip entries, keep a yearly total broken into business, commuting, and personal miles. Schedule C asks for all three figures, and the IRS uses the ratio of business miles to total miles to check that your claimed business-use percentage is plausible.²

One small habit matters more than it looks: record the real numbers. A log full of round entries like “50 miles” and “100 miles” reads to an auditor as estimation. Real trips generate real distances — 47 miles, 103 miles — and a log that shows them looks like what it should look like.

Log Trips as You Drive Them, Not at Tax Time

The IRS expects entries made at or near the time of each trip. A weekly summary that accounts for that week’s driving counts as timely; a spreadsheet you fill in the following April does not.¹

If your records are lost to a fire, flood, or ordinary carelessness, you’re allowed to reconstruct them from available evidence: calendar entries, emails confirming meetings, online map tools to calculate distances between places you visited.³ Reconstructed records carry less weight than originals, but they are far better than nothing. Treat reconstruction as salvage work, not a workflow.

What Actually Counts as a Business Trip

You can’t log correctly if you don’t know which trips belong in the log. The clearest line runs between commuting and business travel: driving from your home to your regular workplace and back is commuting, and commuting is never deductible.¹

Workplace to Workplace

Driving from one work location to another during the same day is deductible. That includes going from your office to a client site, from one client to the next, or from your office to a supplier for materials.⁴ Business errands like picking up supplies or delivering documents to a customer fall into the same category.

Trips From a Qualifying Home Office

If your home office qualifies as your principal place of business, the commuting rule flips. Every trip from home to another work location in the same business becomes deductible business mileage rather than a personal commute.⁵ For anyone who drives frequently for work, this is one of the most practical advantages of a qualifying home office.

Temporary Work Locations

Travel to a temporary work site outside your regular metropolitan area is deductible regardless of whether you have a home office. The IRS draws a hard line at one year: any assignment you realistically expect to last longer than a year is treated as indefinite, not temporary, and travel to it is no longer deductible.⁶ If your expectation changes partway through — a six-month project gets extended to eighteen — travel stops being deductible the moment your expectation changes, not at the twelve-month mark.

Tax Home

The IRS defines your tax home as the city or general area where you regularly work, not where you live.⁷ Travel within your tax home between work sites is deductible; travel from your residence to your tax home is commuting.

Whether You Can Actually Use the Log for a Deduction

Federal law currently blocks most W-2 employees from deducting unreimbursed vehicle expenses on their personal returns.⁸ The people who can still take a federal mileage deduction are:

Self-employed individuals, sole proprietors, freelancers, independent contractors, and gig workers, who claim business mileage on Schedule C of Form 1040.
Armed Forces reservists traveling more than 100 miles from home for reserve duties, using Form 2106.⁹
Qualified performing artists and fee-basis government officials, also on Form 2106.⁹
Employees with impairment-related work expenses.

If you’re a regular W-2 employee who doesn’t fit one of those categories, keeping a log still matters — just not for your tax return. Your employer can reimburse your business driving tax-free under an accountable plan, but only if you submit records showing the date, destination, business purpose, and miles for each trip. Without those records, the reimbursement becomes taxable wages on your W-2.

Where the Numbers Land on Your Return

Self-employed filers report business mileage on Schedule C (Form 1040), line 9. Under the standard mileage rate, you multiply business miles by the current rate (72.5 cents for 2026), add business-related parking and tolls, and enter the total.⁸¹⁰ Part IV of Schedule C is where you report the year’s total miles split into business, commuting, and other personal categories. If you’re depreciating the vehicle under the actual expense method, you use Form 4562 instead of Part IV.¹¹

Reservists, qualified performing artists, fee-basis government officials, and employees with impairment-related work expenses calculate the deduction on Form 2106 and carry it to Schedule 1 (Form 1040), line 12.⁹

W-2 employees seeking reimbursement submit the log to their employer’s payroll or accounting team. Under an accountable plan — one that requires a business connection for each expense, adequate records, and the return of any excess payment — the reimbursement is tax-free and stays off your W-2. If any of those conditions fail, the whole amount becomes taxable wages.

Paper, Spreadsheet, or App

The IRS does not require a specific format. What matters is that the information is timely and complete.

A paper logbook in the glove box is the simplest option. Write down date, destination, purpose, and odometer reading before or after each trip. It’s easy to forget and tedious to total at year-end, but a well-maintained paper log is fully acceptable.

A spreadsheet adds automatic totals. Columns for date, start location, destination, business purpose, and miles driven, with a formula summing the miles, will do the job. A cloud-based spreadsheet also solves the backup problem.

GPS mileage-tracking apps are the most hands-off approach. They detect when the car is moving, record the route, and let you classify each trip as business or personal. They produce year-end reports formatted for tax filing. Some charge a subscription, and an app full of unclassified trips is no better than no log at all, so consistency still matters.

What Happens if the Log Doesn’t Hold Up

Mileage deductions are among the most commonly challenged items in an audit, and the burden of proof falls entirely on you. The IRS does not have to prove your log is wrong; you have to prove it’s right. Without a contemporaneous log, the deduction can be disallowed outright.

Beyond losing the deduction, you’ll owe the tax you should have paid plus interest, and the IRS can add an accuracy-related penalty of 20% of the underpayment if it finds negligence, defined as failing to make a reasonable attempt to follow the tax rules. The same 20% penalty applies if the underpayment amounts to a substantial understatement of income tax.¹²

How Long to Keep the Log

The baseline retention rule is three years from the date you filed the return or two years from the date you paid the tax, whichever is later — that three-year window is the standard period during which the IRS can open an audit.¹³

Longer periods apply in specific situations. If you fail to report income exceeding 25% of the gross income shown on your return, the IRS has six years to audit. If you never file a return or file a fraudulent one, there is no time limit at all.¹³ Keeping mileage logs and vehicle expense receipts for at least six years gives you a comfortable margin, and cloud backups cost nothing.

1
Internal Revenue Service. Publication 463 (2025), Travel, Gift, and Car Expenses – Section: Recordkeeping
2
Internal Revenue Service. Schedule C (Form 1040) – Profit or Loss From Business (Sole Proprietorship)
3
Internal Revenue Service. Recordkeeping
4
Internal Revenue Service. Publication 463 (2025), Travel, Gift, and Car Expenses – Section: Transportation
5
Internal Revenue Service. Publication 587 (2025), Business Use of Your Home
6
Internal Revenue Service. Topic No. 511, Business Travel Expenses
7
Internal Revenue Service. Foreign Earned Income Exclusion – Tax Home in Foreign Country
8
Internal Revenue Service. IRS Sets 2026 Business Standard Mileage Rate at 72.5 Cents per Mile, Up 2.5 Cents
9
Internal Revenue Service. Instructions for Form 2106 (2025)
10
Internal Revenue Service. Topic No. 510, Business Use of Car
11
Internal Revenue Service. Instructions for Schedule C (Form 1040) (2025)
12
Internal Revenue Service. Accuracy-Related Penalty
13
Internal Revenue Service. How Long Should I Keep Records?