Mileage Tracking for Self-Employed Workers: The Complete 2025 Guide

Knowing that mileage is deductible is the easy part — the deduction actually falls apart at the tracking stage. Most self-employed drivers who lose a vehicle-expense claim don't lose it because the trip wasn't legitimate business driving; they lose it because the logbook wasn't kept the way the CRA expects. This guide is about the day-to-day habit of tracking, not the deduction rules themselves — for what's deductible, the 2025 expense limits, and the simplified logbook method's math, see our complete mileage deduction guide.

What to Capture the Moment You Start Driving

A trip logged well takes seconds. Before you pull out of the driveway (or right after you park), get into the habit of capturing five things: the date, your starting point, your destination, why you're making the trip, and the kilometres involved. The specific business purpose is the field people skimp on most — "client meeting" is weaker evidence than "site visit, 45 Elm St. — kitchen renovation quote," and a vague purpose is exactly what an auditor will push back on first.

Odometer readings matter more than most people realize. You need a start-of-year and end-of-year reading to establish total kilometres driven, which is the denominator in your business-use percentage. Missing either reading means you're stuck estimating your total annual mileage after the fact — never a strong position if the CRA asks for support.

GPS Tracking vs. Manual Logging

Manual logging works if you're disciplined about it, but it fails in a predictable way: short trips get skipped in the moment and "added later from memory," which is precisely the kind of reconstruction the CRA doesn't accept as contemporaneous. A paper or spreadsheet logbook also can't prove when an entry was actually written, which matters if your claim is ever questioned.

GPS or address-based tracking removes both problems. The app timestamps the entry automatically, calculates the distance for you instead of relying on an odometer estimate, and creates a record that's inherently contemporaneous because it's generated at the time of the trip. The tradeoff is that you still have to categorize each trip as business or personal — automation handles the distance and the timestamp, not your judgment about why you made the trip.

Common Mileage-Tracking Mistakes That Cost You the Deduction

• Batching entries at the end of the week or month from memory instead of logging as you go
• Recording only the destination, not a specific enough business purpose to justify it
• Never resetting or checking odometer readings at year start and year end
• Rounding trip distances instead of using actual figures
• Skipping short trips because they "don't add up to much" — they do, over a year
• Mixing personal errands into a trip without splitting out the business-only portion

How to Stay Consistent All Year

The habit that actually survives twelve months is the one with the least friction. Log the trip when it happens, not at tax time — a 10-second entry beats a January reconstruction project every time. If you're on the CRA's simplified method, mark your calendar for the 3-month sample window in advance so it doesn't quietly slide past you. And do a quick monthly review of your logged trips rather than waiting until year-end to notice a gap; catching a missing week in February is a five-minute fix, catching it in December is a guess.