Mileage

Keep the mileage log the IRS asks for, see what the miles are worth at tax time, and (if the company pays people back for driving) reimburse them through an entry. (Dated 2026-10-18; ADR-0200.)

Vehicles

Open Mileage, then Vehicles, and add each vehicle with the date it was placed in service in the business. Then:

Expense accounts. Pick the accounts that carry the vehicle's costs (fuel, repairs, insurance, registration). They give the actual-expense figure. An account belongs to one vehicle.
Odometer. Enter the reading on January 1 (or when the vehicle started) and on December 31. The year's total miles come from these; without them the total is the trips you logged, so unlogged personal driving would count as business.
Retire a vehicle when it leaves the business. Its trips stay.

The log

Mileage lists the year's trips. Log one with the date, vehicle, where it started and where it went, the one-way miles, round trip or not, business or personal, the business purpose, and a customer or project if it was for one. IRS Publication 463 asks a car's records to show the date, the destination, the business purpose and the miles of each business use, plus the total miles for the year.

Trips are never edited. Correct voids the trip with your reason and records the corrected one, which names the trip it replaces; Void takes one out with a reason. Both stay on the record.

Recurring trips (a Monday lumberyard run, a monthly client visit) are logged by Log recurring trips through today. Each date is logged once; a trip you voided is not logged again.

Download the log as CSV or PDF for your records or your preparer.

AI agents can propose trips (from a calendar, or a receipt's address): each waits in Proposals until a person approves it.

The deduction

Mileage, Deduction shows each vehicle's year:

the business-use percentage (business miles ÷ total miles);
the standard mileage rate: every business trip at the IRS rate on its date. For 2026 that is 72.5 cents a mile through June 30 and 76 cents from July 1 (IR-2025-128 and IR-2026-29); for 2025, 70 cents. The rates are kept as data with their IRS sources;
actual expenses × business use: the linked accounts' year in the books times the percentage;
which is higher.

It also states the IRS rules on choosing: the standard rate must be chosen in a car's first business year to use it later, five or more cars used at once cannot use it, switching to actual expenses later means straight-line depreciation, and parking and tolls are deductible on top (Publication 463, chapter 4). Your preparer chooses.

The standard-mileage figure is a tax figure: it never posts to the books. The tax-software export carries it as a memo row on Schedule C, line 9 (other deductions on Forms 1120-S, 1065 and 1120), with the vehicle's details for Form 4562 Part V.

Reimbursing miles

If the company pays an owner or employee back for business miles in their own vehicle (an accountable plan), use Mileage, Reimbursements: pick the vehicle, the person and the dates, the expense account and what pays it. Preview shows the miles, the rates and the entry; Post records it through the normal path (an agent's request waits for a person). The same dates cannot be reimbursed twice unless the first is voided.

Over the API and MCP

/v1/mileage/vehicles, /v1/mileage/trips (log_trip proposes for agents), /v1/mileage/recurring, /v1/mileage/deduction, /v1/mileage/log?format=csv|pdf, /v1/mileage/reimbursements. Vehicles, odometer readings, recurring trips, voids and corrections are people's.