Understanding the CRA mileage log requirements is the single most important step before claiming any vehicle expense on your Canadian tax return. Without a compliant logbook, the Canada Revenue Agency can deny your entire deduction for gas, insurance, maintenance, lease payments, and capital cost allowance. This guide covers every required field, retention rules, digital versus paper formats, and the common mistakes that trigger reassessments.
Every Field the CRA Requires
The CRA expects your mileage log to contain specific data points for each trip you drive during the tax year. According to CRA guidelines and the archived Interpretation Bulletin IT-521R, a compliant logbook must record:
- Date of each trip — the calendar date you drove.
- Destination — the city, street address, or name of the location (e.g., “123 King St W, Toronto” or “Acme Corp warehouse, Mississauga”).
- Business purpose — a brief description of why the trip was necessary (e.g., “client consultation,” “supply pickup for job site,” or “vendor meeting”).
- Kilometres driven per trip — the distance for that specific journey, not a daily or weekly lump sum.
- Odometer reading at the start of the fiscal period — typically January 1 for most taxpayers.
- Odometer reading at the end of the fiscal period — typically December 31.
You must also track total personal kilometres and total business kilometres for the year. The CRA uses these totals to calculate your business-use percentage, which determines how much of your actual vehicle expenses you can deduct.
If you use more than one vehicle for business, you need a separate logbook for each vehicle with its own odometer readings and trip records.
What Happens When Your Log Is Incomplete
The CRA does not award partial credit for partial records. If your logbook is missing required fields, the consequences can be severe:
Full denial of vehicle expenses. An auditor who finds entries like “client visit” with no destination, or monthly mileage totals with no individual trip breakdowns, will typically disallow the entire motor vehicle expense claim. That means no write-offs for fuel, insurance, repairs, or lease payments.
Reassessment with interest. When the CRA denies previously claimed expenses, they reassess your return. You owe the additional tax plus compound daily interest dating back to the original filing deadline.
Penalties on top of interest. If the CRA determines that your claim was made knowingly or through gross negligence, you face a penalty of 50% of the understated tax, in addition to the interest. Budget 2024 also introduced compliance order penalties of up to 10% of aggregate tax payable per affected year and non-compliance notice penalties of $50 per day up to $25,000.
Multi-year reassessments. A failed audit for one year often triggers the CRA to review prior years. If your logbook practices were consistently weak, multiple years of deductions can be reversed at once.
The Tax Court of Canada has consistently upheld the CRA’s position. Courts have repeatedly ruled that mileage logs are mandatory for vehicle claims, that estimates without supporting evidence are not accepted, and that the burden of proof falls on the taxpayer.
Digital vs Paper: What the CRA Accepts
The CRA explicitly accepts both paper and digital records for mileage claims. Acceptable digital formats include spreadsheets (Excel, Google Sheets), CSV files, PDFs, and records generated by mileage tracking apps. The only requirement is that your digital log contains the same fields as a paper logbook and that records were maintained contemporaneously — meaning you logged trips as they happened, not reconstructed them months later at tax time.
Paper logbooks work but carry risks. Missed entries, forgotten odometer readings, and illegible handwriting are common problems that undermine credibility during an audit.
Digital logs offer clear advantages for CRA compliance:
- GPS captures start and end locations automatically, eliminating guesswork on destinations and distances.
- Odometer data is recorded without manual entry errors.
- Trip classification (business vs personal) is documented in real time.
- Summaries by month, client, or purpose can be generated instantly.
- Exports produce CRA-ready PDFs with every required field included.
An app like Tripbook handles GPS trip detection, destination capture, and distance tracking automatically. You classify each trip with one tap, and your year-end report contains every data point the CRA expects.
The Simplified Logbook Method
If maintaining a full logbook every year feels burdensome, the CRA offers a simplified alternative — but it comes with conditions.
To qualify, you must first keep a full detailed logbook for one complete 12-month base year. This base year establishes your typical business-use percentage. In each subsequent year, you maintain a logbook for only a continuous three-month sample period. If your business-use percentage during the sample period falls within 10 percentage points of the same three months in your base year, you can apply the base year percentage to the entire year.
If the sample period deviates by more than 10 percentage points, you must either keep a full logbook for that year or establish a new base year.
Key points about the simplified method:
- Your base year log must be fully compliant with every required field.
- The three-month sample must be a continuous period (e.g., January through March, not January plus April plus September).
- You still need odometer readings at January 1 and December 31 each year.
- You must keep receipts for all vehicle expenses regardless of which logbook method you use.
For a detailed walkthrough, see our guide on the CRA simplified logbook method.
Common Mistakes That Make Logs Non-Compliant
Even taxpayers who keep a logbook can fall short of CRA mileage log requirements. These are the most frequent errors that lead to denied claims:
Vague destinations. Writing “around town” or “various clients” instead of specific addresses gives an auditor nothing to verify. Every entry needs a location name or address.
Missing business purpose. A log that records dates and distances but never explains why the trip was necessary fails the CRA’s test. Each entry must state the business reason.
Round numbers every month. A logbook showing exactly 500 km of business driving every single month is statistically implausible. Real driving patterns vary, and round numbers signal reconstruction rather than contemporaneous logging.
No year-start or year-end odometer. Without odometer readings on January 1 and December 31, you cannot calculate total annual kilometres, and without that total, you cannot determine your business-use percentage.
Logging personal commutes as business. Driving from home to your regular place of work is personal — always. The CRA classifies your ordinary commute as a personal expense even if you work overtime or carry tools in your vehicle. The exception is if your home is your established base of business operations and you have no other fixed place of business.
Gaps in the calendar. Weeks of missing entries suggest that personal trips were omitted rather than that no driving occurred. Auditors notice these gaps and draw unfavourable conclusions.
Claiming unrealistic business-use percentages. A personal vehicle claimed at 90% or higher business use raises immediate red flags unless you own a second vehicle for personal driving.
Six-Year Retention Rule
The CRA requires you to keep all vehicle records — logbooks, fuel receipts, insurance documents, repair invoices, lease agreements — for six years from the end of the tax year to which they relate. Your 2026 logbook and expense receipts must be retained until at least December 31, 2032.
This applies to both paper and digital records. If you store records digitally, ensure they remain accessible and readable for the full retention period. Tripbook stores your trip history in the cloud, so your records are available for export whenever the CRA requests them — even years after the original tax year.
For a broader look at CRA record-keeping obligations, see our guide on CRA record-keeping requirements for vehicles. And to understand what triggers a CRA review in the first place, read about CRA audit triggers for small businesses in 2026.
Build a Compliant Log Starting Today
The CRA mileage log requirements leave no room for shortcuts. Every trip needs a date, destination, purpose, and distance. Your odometer must be recorded at the start and end of each year. Records must be kept for six years. And whether you choose paper or digital, the log must be maintained as you drive — not assembled after the fact.
Download Tripbook to automate your CRA-compliant mileage log from day one. Every trip is captured with GPS, every required field is recorded, and your year-end report is ready to present whenever the CRA asks.
