Mileage log for service businesses: what to write down

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If you drive to your customers, your truck or van is one of your biggest business costs. The standard mileage rate turns those miles into a deduction, but only if you can show which miles were for business. A simple log, kept as you go, is what makes that possible.

What the IRS asks you to record

IRS Publication 463 has a table of what you need to prove car expenses. For car use it lists the mileage for each business use and the total miles for the year, the date of each use, your business destination, and the business purpose. It also says you should record these at or near the time of the trip, and that a log kept on a weekly basis, accounting for that week's use, counts as a timely kept record. It also says a record you prepare on a computer is considered an adequate record.

In plain terms, each trip in your log should have:

• Date of the trip.
• Miles driven for business on that trip.
• Purpose: who or what it was for, like "Weekly mow, Johnson yard" or "Supply run for Oak St job." Adding the place helps cover the destination.

Once a year, also write down your vehicle's total miles (an odometer reading on January 1 and December 31 works), since the IRS table asks for total miles for the year too.

A sample log

Example (made-up trips):
Mar 3: 14 miles, estimate and first mow, Johnson yard, Elm St.
Mar 3: 9 miles, supply store, line trimmer parts.
Mar 4: 22 miles, route day, five weekly customers.

That's all a trip needs. The hard part isn't the format, it's writing it down the same day instead of rebuilding it from memory in April.

Which miles count

Trips between job sites, to the supply store, and to meet a customer are the kind of miles service businesses log. Publication 463 says travel between your home and your main or regular place of work is generally personal commuting, which you can't deduct, but it lists exceptions, including when your home is your principal place of business. Which miles count for you depends on your setup, so check with a tax professional.

The 2026 IRS standard mileage rates

The IRS changed the business standard mileage rate partway through 2026. Its standard mileage rates page lists:

• January 1 – June 30, 2026: 72.5 cents per mile (IRS announcement IR-2025-128)
• July 1 – December 31, 2026: 76 cents per mile (IRS announcement IR-2026-29)

Because the rate changed mid-year, the date on each trip matters: it decides which rate applies. That's another reason to log trips as you drive. There are also IRS rules about when you can choose the standard rate instead of actual vehicle expenses, so ask a tax professional which method fits you.

A worked example

Example (made-up numbers): you drive 3,000 business miles from January through June (3,000 × $0.725 = $2,175) and 3,000 business miles from July through December (3,000 × $0.76 = $2,280). That's a $4,455 estimated deduction for 2026. It isn't money back. It lowers the profit you're taxed on.

Our 2026 mileage deduction calculator does this math for you: enter the miles for each half of the year and it adds them up at the two IRS rates.

Tips that keep a log honest

• Log at the end of each day, or at least weekly, while you still remember the stops.
• Keep business and personal trips apart. If you stop at the store for groceries on the way home, only the business part of the drive belongs in the log.
• Keep the log with your other records for as long as you keep your tax records.

Keep your mileage log in MiniCFO.io

MiniCFO.io has a built-in mileage log. Each trip takes a date, business miles, and a purpose or customer, the same three things this guide covers. It applies the IRS standard mileage rate for each trip's date. Trips are saved on this device, so log them on the same phone each time. Your trips sit next to your income and expenses, so you see the whole picture in one place.

This guide is general information and an estimate, not tax advice. Rules change and your situation matters, so check with a tax professional.

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