Short answer: if you kept a full CRA logbook for one complete year (your base year) and your driving hasn't really changed, you don't need to log every trip of 2026. A continuous three-month sample logged inside 2026, run through the CRA's formula, can set your business-use percentage for the whole year, as long as the result lands within 10 points of your base year. Starting with October 1, October to December still fits. If you never kept a base year, a sample can't help you for 2026.
Here is the moment this page is for. You're self-employed in Canada: a delivery driver in Mississauga, a mobile dog groomer in Calgary, a contractor driving between job sites. Last year your accountant had you keep a proper logbook, every trip and every kilometre, and you did it. Then January came, the logbook went in the glovebox, and nobody mentioned it again until this month, when the accountant asked what your business use is going to be for 2026. You're not facing nine months of reconstruction. The CRA has a shortcut for people in exactly this spot.
First: why you need a percentage, not a rate
Most of what you'll find online about "CRA mileage" is the per-kilometre rate. For 2026 that is 73¢ for the first 5,000 km and 67¢ after that (77¢ and 71¢ in the Northwest Territories, Yukon and Nunavut). Finance Canada describes those rates as allowances paid by employers to employees. They are not a deduction a self-employed person can claim.
When you're self-employed, you claim your actual vehicle costs on Chart A of Form T2125: fuel, insurance, licence and registration, maintenance and repairs, interest on a car loan, leasing costs, and capital cost allowance. You can deduct only the part you paid to earn income, so everything gets multiplied by your business-use percentage: business kilometres divided by total kilometres. The CRA asks you to keep a record of both numbers, and the logbook is that record. (Parking for business stops is the exception: it's deductible in full and isn't pro-rated.)
Full logbook, base year, sample: the three pieces
| Piece | What it is |
|---|---|
| Full logbook | For every business trip: the date, destination, purpose and kilometres. Plus the odometer reading at the start and end of your fiscal period. |
| Base year | One complete year kept as a full logbook. It shows your normal business use, month by month, and has to stay representative of how you use the vehicle. |
| Three-month sample | In a later year, a full logbook kept for just three continuous months. The formula below turns it into an annual figure. |
The formula, worked through
The CRA's calculation is:
(Sample period % ÷ base year same-period %) × base year annual % = annual business use
The middle term is the clever part: your sample is compared with the same months of your base year. So if October to December is always your busiest stretch, the formula expects a high sample and scales it back down. You aren't penalised for picking the season you happen to be in.
Say your 2025 base year showed 62% business use for the year, and 70% for October to December 2025 alone (holiday orders pick up). You log October 1 to December 31, 2026 in full, and it comes out at 74%.
- 74 ÷ 70 = 1.057
- 1.057 × 62% = 65.5% business use for 2026
- Your accepted range is 62% plus or minus 10 points, so 52% to 72%. 65.5% is inside it.
If your 2026 vehicle costs before capital cost allowance come to $9,800 (fuel, insurance, maintenance, licence), the business part is about $6,419, and the same 65.5% applies to your capital cost allowance. The CRA's own example works the same way: a 49% base year, a sample that projects to 54%, accepted because it falls between 39% and 59%.
When the sample fails
Change one number. Your sample comes out at 88% instead of 74%, because you added a second delivery app and now drive almost nothing personal. Then (88 ÷ 70) × 62% = 77.9%, which is outside 52% to 72%. The CRA's position is that the base year is no longer a good guide to that year. The sample is reliable only for the three months you logged, and you need real records for the other nine months, or a new base year.
That's also the honest answer if your work changed a lot since the base year: a different job, a second car taking the personal driving, a move. The base year has to stay representative of normal use, and a sample can't paper over a change like that.
Why October is the line
A sample covers three continuous months and sets your business use for the year, so the clean reading is that all three months sit inside 2026. Today that means October 1 to December 31, and only if you can show the first days of October honestly. That's easy if something was already recording your drives, or if your delivery apps' trip histories and an odometer figure on a service invoice let you fill in those few days. The CRA's page doesn't say a sample can't cross into January, but a sample starting mid-October would end in 2027, and you'd be the one explaining why that counts for 2026. Ask your accountant before you rely on it.
Tip: the formula needs your base year broken down by month, not just its annual total. Before you start, open last year's logbook and work out business kilometres and total kilometres for October to December 2025. If you only ever wrote down a year-end total, you can't do the calculation, and the sample won't help.
What to record from today
- Odometer on day one and on the last day of the sample, and at year end.
- Every business trip: date, destination, purpose (“Uber Eats, evening shift” or “Henderson job site, drywall delivery”), kilometres.
- Total kilometres for the period, from the two odometer readings, so personal driving is accounted for too.
- Receipts for the whole year, not just the three months: the sample sets the percentage, but the costs it's applied to are the year's.
Then keep the base year logbook. The CRA says it must be kept for six years from the end of the last tax year it's used for. If your 2025 base year supports samples through 2029, it stays in the drawer until the end of 2035.
Who this doesn't help
- No base year. The simplified method only exists after one full year of logbook. For 2026 you need the most complete full-year record you can put together; the CRA's page doesn't describe a shortcut for that. If your fiscal period is the calendar year, a full logbook from January 1, 2027 becomes the base year that makes 2028 onwards easy.
- Employees paid a car allowance. That's the 73¢/67¢ rule and different forms. This page is about self-employed income on Form T2125.
- Quebec residents also file a provincial return with Revenu Québec, which has its own requirements. Check those too.
- Australians use a different system: a 12-week logbook valid for five years. See the ATO 12-week logbook.
Our app: TaxMiles, the app this site is for, has a Logbook in its Tax Toolkit when your tax region is Canada, with both a base year logbook and a 3-month sample. You enter the start date (it can be a date that has already passed) and the opening odometer. Drives are recorded in the background in kilometres, and drives you haven't marked Business or Personal yet don't count as business. When you close it with the closing odometer, it shows business and total kilometres, the business-use percentage, and any odometer kilometres it didn't track. If your base year was also kept in TaxMiles, it runs the CRA formula and tells you whether the result is within 10 points; a paper base year means doing the division yourself. It stores no odometer reading per trip: per-trip odometer figures in the export are calculated from the opening reading plus GPS distance, and labelled as calculated. The logbook is free to use; exporting it as CSV is part of Pro. A paper notebook and two odometer photos do the same job if you'd rather.
Frequently asked questions
Can I claim the CRA's 73 cents per kilometre as a self-employed driver?
No. The 2026 rates of 73 cents for the first 5,000 km and 67 cents after that (77 and 71 cents in the territories) are the most an employer can pay an employee tax-free per kilometre. A self-employed person claims actual vehicle costs, such as fuel, insurance, licence and registration, maintenance, interest, leasing and capital cost allowance, multiplied by business-use percentage on Form T2125. The logbook is what proves that percentage.
Which three months can I use for the sample?
The CRA's page doesn't name specific months. Its formula compares your sample to the same months of your base year, so a busy or quiet season is adjusted for. Keep the three months continuous and inside the year you are claiming. If your sample can't sit inside 2026, ask your accountant before relying on it.
What if my sample result is more than 10 points away from my base year?
Then the CRA says the base year is not a good indicator for that year, and the sample is only reliable for the three months you logged. You need actual records for the rest of the year, or a new base year.
I never kept a full-year logbook. Can I start a 3-month sample now?
No. A sample only works against a complete 12-month base year. For 2026 you need the best full-year record you can assemble. If your fiscal period is the calendar year, starting a full logbook on January 1, 2027 gives you a base year that later samples can lean on.
How long do I keep the base year logbook?
The CRA says six years from the end of the last tax year you use it to establish business use. If a 2025 base year supports samples through 2029, keep it until the end of 2035.
Three months, not twelve
Set TaxMiles to Canada, start a 3-month sample from the Logbook, and let it record the trips in kilometres while you drive.
Get TaxMilesRelated reading: mileage deductions in the UK, Canada and Australia, which explains why the 73¢ rate isn't yours to claim, and the ATO 12-week logbook, the Australian version of the same idea. The Canada page has the 2026 CRA figures in one place.
Sources: the CRA’s motor vehicle records page (full and simplified logbook, the formula, the 49% example, six-year retention), its motor vehicle expenses on Form T2125 and deductible expenses pages, and Finance Canada’s 2026 automobile limits and allowance rates. Checked October 6, 2026.
This article is general information for self-employed people filing with the Canada Revenue Agency, not legal, tax or accounting advice. Check the CRA’s current pages or ask a tax professional about your situation. TaxMiles is published by Gigabyte LLC, the company that wrote this page, and is not affiliated with the CRA. Phone Diet, RecipeScan and Trending Music below are also our apps. Apple and iPhone are trademarks of Apple Inc., which doesn’t endorse this article.