What should a mileage record book include?
CRA’s guidance separates the information about each business trip from the information about the vehicle as a whole. A useful mileage log book therefore combines trip-by-trip details with the broader vehicle mileage record for the fiscal period.
Date,destination,business purpose andnumber of kilometres driven.
Total kilometres driven, kilometres driven to earn business income, and odometer readings at the beginning and end of the fiscal period.
Record the relevant date and odometer reading when a vehicle is bought, sold or traded during the fiscal period.
A list of business kilometres alone does not show the same information as a trip-by-trip log plus the vehicle’s total use.
The full-year logbook is the reference point.
CRA describes an accurate logbook maintained for the entire year as the best evidence of the business use of a vehicle.
The purpose of the log is not simply to produce a number at the end of December. Keeping the trips throughout the year preserves the information behind that number: which driving was business, which driving was not, and how the business-use total was built.
If a full logbook is later used as the base year for CRA’s simplified-logbook method, that complete year becomes the benchmark against which a later sample period is compared.
Business kilometres need a denominator.
When a vehicle is used for both business and personal driving, total vehicle use provides the context for the business kilometres.
The percentage can then matter when vehicle expenses are allocated between business and personal use. The expense calculation itself is a separate step from maintaining the mileage log.
Continue to the CRA motor vehicle expenses guide“Three-month logbook” comes after a full base year.
The simplified method does not begin by recording only three months. CRA first requires a complete base year.
Maintain a complete logbook for one full 12-month period.
In a later year, maintain a sample for a three-month period corresponding with the same period in the base year.
The calculated annual business use must remain within CRA’s permitted 10% range of the base-year result.
Base-year annual business use is 49%. The comparable base-year three-month period is 46%, while the later three-month sample is 51%.
Two vehicles should not disappear into one mileage total.
CRA says to maintain a separate record for each business vehicle, including its total kilometres, business kilometres and operating costs, and to calculate each vehicle’s expenses separately.
The numbers above are illustrative. HonestMile Pro supports multiple vehicles so trips can remain associated with the vehicle that produced them.
Filing the return is not the end of the record.
CRA generally requires records and supporting documents to be kept for six years from the end of the tax year to which they relate.
A full 12-month logbook used as the base year for the simplified method has a special timing rule: CRA says to keep it for six years from the end of the tax year for which it was last used to establish business use.
Different circumstances can affect record-retention requirements. Refer to current CRA guidance when deciding how long a particular record must be kept.
Quick recordkeeping answers.
What should a mileage log book include?
A useful business mileage record should show the date, destination, business purpose and kilometres for each business trip, together with the vehicle’s total kilometres and beginning and end odometer readings for the fiscal period.
Do I need an entry for every business trip?
CRA’s logbook guidance says each business trip should list the date, destination, purpose and number of kilometres driven.
Do I need opening and closing odometer readings?
CRA says to record the odometer reading for each vehicle at the beginning and end of the fiscal period.
Can I start with only a three-month sample?
Not under CRA’s simplified-logbook method. A complete base year comes first; the three-month sample may be used in a later year if the method’s conditions are met.
Is the mileage log itself the vehicle-expense deduction?
No. The log supports the business-use record. Calculating deductible motor vehicle expenses is a separate step.