CRA Form T2125 Business Mileage Log Rules | Simplified vs Detailed | NationRules
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Self-Employment

CRA Form T2125 Mileage Rules

Understand detailed vs. simplified mileage logs and calculate your business vehicle tax deductions.

Vehicle Business Use Calculator

Input your mileage log details to calculate your deductible business expenses:

Fuel, repairs, insurance, lease, etc.

Simplified vs. Detailed Mileage Logbooks

The CRA allows two main methods to document business vehicle usage:

  • Detailed Logbook (First Year): You must keep a logbook for a full 12-month period to establish a **base year** of business use. Each entry must list: date, destination, business purpose, and starting/ending odometer readings.
  • Simplified Logbook (Subsequent Years): If your business usage remains stable (within 10% of your base year), you can keep a detailed logbook for a **representative 3-month period** instead of the full year. You then use that 3-month sample to calculate your annual deduction percentage.
  • Capital Cost Allowance (CCA): You can also write off a portion of the vehicle's purchase price using CCA. For passenger vehicles (Class 10.1), the maximum depreciable cost base is capped (e.g. $37,000 + taxes).
Form T2125 Rules
Deduction ScheduleForm T2125 Part 17
Audit Retention Requirement6 Years
Detailed Base Log12 Months (Year 1)
Simplified Log Period3 Months (Year 2+)