IRS Mileage Log Requirements: What to Record, Which Trips Count

What must an IRS mileage log show?

The law requires proof of each business use of the car, not a log by that name or in a set format, and a log is the usual way to give that proof. If your preparer asked for a log, or an IRS letter asks for proof of business miles, the proof must show each trip's date, where you went, why, and how many miles, plus the car's total miles for the year.

Federal law allows no deduction for a car or other vehicle unless the taxpayer substantiates it by adequate records (a written record of each trip) or by sufficient evidence, such as a calendar or invoices, that corroborates the taxpayer's own statement (26 U.S.C. 274(d)). This rule does not apply to a qualified nonpersonal use vehicle, such as a delivery truck with seating only for the driver (Publication 463). The regulation lists an account book, diary, log, trip sheet or similar record as the form adequate records take (26 CFR 1.274-5T).

Source: Publication 463, Table 5-1. Its sample daily log adds odometer start and stop columns, which are not required but make each figure checkable.

Logging only a year-end total is not enough. One narrow example: if your only business driving is deliveries or sales calls on an established route, you may record the route's length once, each trip's date and the year's total miles, with no written purpose per trip (Publication 463; 26 CFR 1.274-5T).

A case is not simple when your preparer or an IRS letter asks for proof, when the log was never kept or was rebuilt at year end, when the car serves a home office or a second workplace, when more than one vehicle is involved, or when a partnership or corporation owns the car. Gather the odometer reading at the start and end of the year, your calendar, client addresses or invoices, and the purpose of each trip.

Do I need a mileage log with both the standard mileage rate and actual expenses?

Yes. Both methods need a record of business miles. The standard mileage rate replaces the record of what the car costs to run; it does not replace the record of how far you drove for business. The deduction is the rate times the business miles traveled (Revenue Procedure 2019-46, section 4.01; Tax Topic 510).

With actual expenses, the log sets the business share of costs such as gas, insurance and depreciation. Business miles divided by total miles gives the percentage (Publication 463). If you depreciate the car, keep records of its business use for each year of the recovery period (Publication 463). To choose between the methods, and for the business-use test, see standard mileage rate or actual car expenses.

The standard rate changed in the middle of the tax year this page covers, so each trip's date matters: 72.5 cents per mile for January through June and 76 cents per mile for July through December (Announcement 2026-11).

Is an app, a spreadsheet or a notebook enough?

Yes, if it holds the details above and is accurate. The regulation names no required format or product. A record kept on a computer counts as written when it is made in a computer memory device with a logging program, and Publication 463 says a record prepared on a computer is an adequate record (26 CFR 1.274-5T; Publication 463).

Three traps apply to any format:

• Missing purpose. Automatic tracking usually records miles and times, not why you drove. A written statement of business purpose is generally required unless the purpose is evident from the circumstances, so add it to each trip (26 CFR 1.274-5T).
• Estimates. Publication 463 says you cannot deduct amounts you approximate or estimate.
• Records you cannot open later. If you keep records on a computerized system, you must be able to produce legible records that support the entries on your return and reconcile with your books (Publication 583). Export the log at year end instead of relying on an account you might close.

How often must I update the log?

Make each entry at or near the time of the trip. A day-by-day log is not required: a log kept weekly for that week's use counts as made at or near the time. A log written later is not an adequate record on its own, and your own statement then needs strong corroboration, such as calendar entries, invoices and messages with clients (26 CFR 1.274-5T; Publication 463).

If you log only part of the year, the IRS accepts that for the whole year only when other evidence, such as invoices, shows those periods are representative. For that, and for a log that was never kept or was lost, see rebuilding a mileage log.

Which trips count as business, and which are commuting?

Driving between home and your regular workplace is commuting, and commuting is never deductible, however far it is and even if you make calls or carry tools on the way (Publication 463).

The first six rows assume your home is not your principal place of business; see the home-office section below.

A work location is temporary when the work there is realistically expected to last, and does last, one year or less. If you expect it to last longer than a year, it is not temporary even if it ends sooner, and it stops being temporary when your expectation changes. Your metropolitan area is the city plus the suburbs treated as part of it (Publication 463; Schedule C instructions, line 44b).

A personal detour needs care. Between two workplaces, if you leave the direct route for a personal reason, you cannot deduct more than the direct trip would have cost, so log the extra miles as other miles (Publication 463). A brief stop such as lunch between two business stops does not interrupt business use (26 CFR 1.274-5T).

Do trips from my home office count?

Yes, when the home office qualifies as your principal place of business. Trips between that home and another work location in the same trade or business are then business miles, whether the other location is regular or temporary and however far away (Publication 463; Schedule C instructions, line 44b; Revenue Ruling 99-7).

The test comes from the home office rules. Your home office qualifies as the principal place of business if you use it exclusively and regularly for administrative or management activities of the business, and you have no other fixed location where you conduct substantial administrative or management activities (Publication 587). That publication also tells you to weigh the relative importance of the work done at each location and the time spent there. A home that is not your principal place of business leaves you under the ordinary commuting rules above. For the home office deduction itself, see simplified or actual method.

Only a home that is your principal place of business counts for trips; a home office that qualifies only because you meet clients there, or as a separate structure, does not (Schedule C instructions, line 44b). If you work for your own corporation as an employee, the home use must also be for your employer's convenience (26 U.S.C. 280A(c)(1)). Publication 587 allows an employee no home-office deduction, but that does not by itself make home-to-site trips commuting: when the home meets the principal-place-of-business test, the corporation can reimburse those trips under an accountable plan, excluded from your wages if the plan's rules are met (Revenue Ruling 99-7; Publication 5137).

What if I also use a coworking space or a second location?

It depends on your home office. If your home is your principal place of business, trips between home and the desk, and from the desk to a client, are business miles. If not, driving from home to a desk you use regularly is generally commuting, and desk to client is business. The IRS has no coworking-specific rule: this applies the regular-workplace rule, so how often you use the desk and what you do there can change the answer.

Publication 587 says a fixed location outside the home where you do substantial administrative or management work, such as billing, bookkeeping or scheduling, can keep the home from qualifying. Substantial work that is not administrative, such as meeting or serving clients at a fixed location, does not (Publication 587). Where you do the administrative work, and how much, is something a log of miles cannot show by itself, so note in the log where each workday's work took place.

Do I list total miles if only some are deductible?

Yes. List every mile the odometer moved, then split it into business, commuting and other; only the business miles are deductible. Schedule C, Part IV is for a sole proprietor who uses the standard mileage rate, leases the vehicle or has a fully depreciated one, and does not have to file Form 4562 for another reason. Form 4562, Part V is for a vehicle you depreciate, or when you must file that form anyway. Each asks for the date placed in service, the business, commuting and other miles, and whether you have written evidence for the deduction (Schedule C instructions, line 9; Schedule C form; Form 4562; 26 CFR 1.274-5T).

To fill them in, take the year-end odometer reading minus the start-of-year reading for the total, add the business trips for the business figure, add the commuting trips for the commuting figure, and treat the remainder as other. An odometer that reads 40,000 on January 1 and 52,000 on December 31 gives 12,000 total miles. If the log shows 7,500 business miles and 600 commuting miles, the other 3,900 are personal, and only the 7,500 are deductible.

Keep a separate log for each vehicle; the Schedule C instructions ask for the Part IV information on an attached statement for each additional vehicle (Schedule C instructions).

Does the rule change when a partnership or corporation is involved?

The substantiation rule applies to any taxpayer claiming a deduction for a car, including a partnership or corporation that owns one (26 U.S.C. 274(d)). Such an entity has no Schedule C; it reports the mileage of a vehicle used by an owner or related person on its own Form 4562, Part V (Form 4562).

A log proves the miles; it does not create a deduction. If you work for your own corporation as an employee, an employee's unreimbursed car cost is generally not deductible on a personal return (Publication 463); the corporation can repay the miles from your log instead. If the corporation instead provides you a car, commuting and other personal use is generally a taxable fringe benefit it must value and report on Form W-2 unless you pay for that use, so keep the commuting and other-miles split even when you claim no deduction (Publication 15-B). A partner can deduct a car cost the partnership does not repay only if the partnership agreement required the partner to pay it, as an unreimbursed partnership expense on Schedule E (Schedule E instructions).

When a corporation reimburses you, you adequately account to it with the date, destination, business purpose and miles of each trip, recorded at or near the time. If you own, directly or indirectly, more than 10% of the corporation's stock, you are related to your employer and must also be able to prove the expenses to the IRS (Publication 463). For repayment rules, see reimbursing owner expenses; for cars bought through an entity, buying a vehicle through your business.

Example

These examples use miles only.

A photographer with a home office

A photographer's spare room is used only for billing and bookkeeping, there is no other office, and the room meets the principal-place-of-business test in Publication 587, so trips from home to a shoot are business trips. One day the odometer moves 16 miles: 11 on the round trip to a shoot, then a separate 5-mile round trip to the gym. The log shows 11 business miles with the shoot as the purpose, 5 other miles, and 0 commuting miles.

A bookkeeper visiting a client

A bookkeeper works from a qualifying home office and drives 20 miles round trip to a client. The log records the date, the client's city, the purpose (quarterly review of the books) and 20 business miles. Because the home is the principal place of business, the trip from home counts.

A freelancer with a coworking desk

A freelancer who works at the same rented desk every weekday, 12 miles each way, has no qualifying home office. The 24 miles each day are commuting. One day the freelancer drives from the desk to a client 10 miles away and back to the desk. Those 20 miles are business miles. Whether the drive from home to the desk could ever count depends on the home-office test above.

Different for you?

• Your preparer asked for a log, or an IRS letter asks for proof of business miles: which trips are deductible, and whether your records hold up, turn on facts a log does not settle alone, such as the home-office test, a second workplace and mixed trips. Bookkeeping help fits when the records are the gap. If the IRS has opened an audit, see the IRS audit guide and which Schedule C expenses get questioned.
• You kept no log, or lost it: use rebuilding a mileage log. Several years without a log can also mean books to catch up, which is bookkeeping help.
• You are choosing between the standard rate and actual expenses, or switching: see standard mileage rate or actual car expenses.
• You drive for a rideshare or delivery platform: see rideshare and delivery driver deductions.
• An LLC or S corporation owns the car, or reimburses you for it: see buying a vehicle through your business and reimbursing owner expenses.
• The car is used for both business and personal driving, with parking, tolls and receipts to track, or you want to know how long to keep the log: see business percentage for mixed-use expenses, IRS receipt requirements and how long to keep business records.
• You drive in Canada: Canada's logbook rules differ; see the CRA vehicle logbook guide.