Business Mileage Log: What the IRS Expects You to Record

If you drive for your business, your car may be one of your biggest deductions. For the 2026 tax year, the IRS standard mileage rate for business use is 72.5 cents per mile — so 5,000 business miles is worth a $3,625 deduction. But the deduction is only as good as your records. Here is what a mileage log for taxes needs to show and how to keep one without thinking about it.

Which trips count as business miles?

Generally deductible:

• Driving to meet clients or customers
• Trips to the post office, supplier or bank for the business
• Driving to craft fairs, markets, pop-ups or trade shows
• Travel between two work locations
• Business errands, such as picking up materials

Generally not deductible:

• Commuting between your home and a regular workplace, such as a studio you rent
• Personal errands, even if you do a business errand on the same trip (only the business portion counts)

If your home is your main place of business, trips from home to other business locations usually count as business travel. The rules have nuances, so check IRS Publication 463 or ask a tax professional if you are unsure.

What your mileage log must record

The IRS expects records made at or near the time of the trip. For each business trip, write down:

Field	Example
Date	Oct 14, 2026
Starting point and destination	Home → Riverside Craft Fair
Business purpose	Sell products at booth #12
Miles driven	38
(Optional) Odometer start and end	41,206 → 41,244

Also record your odometer reading on January 1 and December 31 (or when you start and stop using the vehicle for business). That gives you total miles for the year, which you need to show the business-use percentage.

Vague entries like “client meeting — 40 miles” every Tuesday look reconstructed. Specific, contemporaneous entries are what hold up.

Standard mileage rate vs actual expenses

You can usually choose one of two methods:

1. Standard mileage rate. Multiply business miles by the IRS rate (72.5 cents for 2026). You can still deduct business parking fees and tolls separately. Simple, and it only needs the mileage log.

2. Actual expenses. Add up gas, insurance, repairs, registration, depreciation and more, then multiply by your business-use percentage. It can produce a bigger deduction for expensive vehicles or high running costs, but you must keep receipts for everything.

One important rule: if you want to use the standard mileage rate for a car you own, you generally need to choose it in the first year you use the car for business. See the IRS standard mileage rates page for current rates and conditions.

A quick example

An Etsy seller drives 4,200 business miles in 2026: post office runs, supply trips and eight weekend markets.

• Standard mileage deduction: 4,200 × $0.725 = $3,045
• Plus market parking: $96
• Total vehicle deduction: $3,141

For a seller in the 12% bracket who also pays self-employment tax, that deduction can save several hundred dollars in tax.

A routine that keeps your log accurate

1. Log trips the same day. Use a spreadsheet, a notes app or a paper log in the car — whatever you will actually use.
2. Use the same place names. “Post office,” “Supplier — Main St” and so on make totals easy.
3. Add trips weekly to your main expense records if you log them elsewhere first.
4. Total miles monthly. It takes a minute and catches gaps early.
5. Record odometer readings on January 1 and December 31.

Where mileage goes on your return

Sole proprietors usually report vehicle expenses on Schedule C, line 9 (car and truck expenses), with vehicle details in Part IV. Our guide to Schedule C expense categories shows how mileage fits with your other deductions, and our article on how much to set aside for taxes explains why every deduction lowers both income tax and self-employment tax.

The bottom line

A mileage log is the easiest big deduction to lose. Record date, destination, purpose and miles for every business trip, note your odometer at the start and end of the year and total it monthly. An expense tracker with a built-in mileage log that applies the current IRS rate for you turns it into a ten-second habit.