CRA mileage log requirements: what to record, and the 3-month logbook shortcut

To claim business use of a vehicle, the CRA expects a logbook showing, for each business trip, the date, the destination, the reason for the trip and the kilometres driven, plus the total kilometres for the year. After you keep one full 12-month logbook as a base year, you can keep a log for just one continuous three-month sample period in later years, as long as the results stay within 10 percentage points of the base year.

Updated October 28, 2026. Rules from the CRA page on documenting the use of a vehicle, linked below.

What a full-year log needs

  • Each business trip: date, destination, purpose, and kilometres driven.
  • The odometer reading at the start and end of the year, so total kilometres can be shown.
  • Driving from home to a regular work location is personal, not business. Driving to job sites, suppliers and clients from your place of business usually is business.

The simplified (sample period) logbook

  • Base year: one full, typical 12-month logbook. It does not have to be a calendar year. Keep it for six years after the last tax year it supports.
  • Later years: a logbook for at least one continuous three-month period.
  • Test 1: the sample period's business-use percentage must be within 10 percentage points of the same three months in the base year.
  • Test 2: the annual business use you calculate must be within 10 percentage points of the base year's annual figure.
  • Formula: (sample period % divided by base year same-period %) times base year annual % = business use for the year.

Worked example (the CRA's own numbers)

Base year: 49% business use for the year, 46% for April to June. This year, a log kept for April to June shows 51%. Calculation: 51 divided by 46, times 49 = about 54%. That is inside the 39% to 59% range, so 54% business use can be claimed for the year. If the test fails, the sample only supports those three months, and the rest of the year needs other records; start a new base year.

Why trades should keep one

A pickup or van used for jobs is often the largest expense after labour. Without a log, the CRA can reduce the business share at review, and the GST input tax credits on fuel and repairs go with it. A notes app or a paper book in the glovebox both work, as long as the four facts are there for each trip.

FAQ

Does the CRA accept a phone app?
Yes, if it records the date, destination, purpose and distance for each trip. The format is not set.

Do I need a log if the truck is 100% business?
Yes. A 100% claim is the one most likely to be questioned, and the log is your evidence.

Can I rebuild a log at year end from my calendar?
A reconstructed log is weaker evidence than one kept at the time. Calendar entries, invoices and fuel receipts can support it, but start keeping one now.

Does an employee use the same rules?
The same log supports an employee's claim or a taxable benefit calculation for a company vehicle.

Every vehicle claim is different, so talk to your accountant about your own percentage. To estimate your claim, try our free Vehicle Claim Calculator at murtaghco.ca/vehicle-claim-calculator.

Sources: CRA: documenting the use of a vehicle.

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