A mileage deduction is only as good as the record behind it. The rules are short, and a spreadsheet can meet them easily. This page sets out what the IRS asks for in its recordkeeping guidance and how the 2026 rates work. It is general information, not tax advice, so confirm your own situation with a tax professional.
The four details for each business drive
For each business use of your car, IRS Publication 463 describes a record that shows:
- Date of the drive
- Destination, the place you drove to
- Business purpose, why you went
- Miles driven for the trip
The publication’s sample daily log also includes odometer start and stop readings. You also need your total miles for the year, so you can show the business share.
How the record should be kept
- Written. A computer-prepared record counts as written.
- Close to the time. A record made at or near the time of the drive carries the most weight. The IRS treats a log that accounts for the week’s driving as timely.
- Actual, not estimated. Estimates are not deductible.
- Round trips can be one entry. Several stops that make one continuous trip can be recorded together.
- Some drivers have a shortcut. The publication describes a lighter record for a salesperson on an established route. Read that section before relying on it.
What does not count
Driving between your home and your regular place of work is commuting, and it is not deductible mileage. That is why Calendar Mapper has a commute setting that subtracts a normal commute from the first and last drive of each day. Also confirm whether you can deduct at all. For employees, unreimbursed mileage is generally treated differently from mileage reimbursed by an employer. See whether expense reimbursements are taxable.
The 2026 standard mileage rates
Instead of tracking the actual cost of operating a car, you can multiply business miles by the standard rate. The IRS set the 2026 business rate at 72.5 cents per mile in Notice 2026-10, then revised it to 76 cents per mile for travel on or after July 1, 2026. Because the rate changed mid-year, a 2026 log needs to show which miles were driven before and after July 1.
That is easy in a spreadsheet, because the date is on every row. Total the miles before July 1 and the miles from July 1 separately, then multiply each by its rate. Rates change, so check the IRS page above for the current figure before you file.
Meeting these rules in Google Sheets
| The IRS asks for | In a Calendar Mapper log |
|---|---|
| Date | The date of each appointment and a subtotal for each day |
| Destination | The event’s location, and the “from” and “to” of each drive |
| Business purpose | The event title and description. Write the reason for the visit there. |
| Miles | Driving distance from Google Maps for each drive, with a total |
| Odometer readings | Not recorded. Keep these separately if you use them. |
Two habits keep the record strong. Put the purpose in the event title when you create the event, so the record is made at the time. And run the import weekly or monthly rather than once a year, or let Auto-Update do it.
To build the log, follow How to make a mileage log from Google Calendar. To total it by client or month, see this pivot table guide. For the broader picture, read How to track your mileage for business taxes and when to track your mileage.