Use two totals
A monthly cash-flow total answers, "How much money leaves the household budget?" Include the payment, insurance, fuel or charging, maintenance, parking, registration, and seasonal tire costs. Do not add depreciation to that cash figure because it is not normally a bill.
A depreciation-based ownership estimate answers, "What does using and owning the asset cost?" Include operating expenses and the estimated loss in vehicle value, but exclude the full loan payment. Principal payments convert cash into equity in the vehicle rather than being entirely consumed as an expense.
A precise economic-cost calculation would add loan interest rather than the full payment. If the payment amount does not separate principal and interest, review the financing agreement before comparing vehicles financed at different rates.
Build every cost on the same period
- Monthly: payment, insurance, fuel or charging, parking, routine maintenance allowance.
- Annual: licensing, registration, seasonal tire changes or replacement allowance, memberships, and expected repairs.
- Economic: depreciation and financing interest, where known.
- Occasional: deductibles, major repairs, accessories, tolls, and unexpected parking.
Convert annual amounts to monthly by dividing by 12. Convert a bill covering another period using its actual number of months instead of guessing.
Depreciation needs a realistic resale estimate
Depreciation is the difference between the vehicle's value now and its likely value later, divided across the period being compared. It varies with age, kilometres, condition, market demand, damage history, and vehicle type. The Financial Consumer Agency of Canada warns that rapid depreciation can create negative equity when a loan balance stays above the vehicle's value.
Cost per kilometre changes with driving
Dividing annual cost by annual kilometres is useful, but it does not mean all costs disappear when kilometres fall. Insurance, parking, registration, and much of depreciation can remain. A lower annual distance can therefore raise the calculated cost per kilometre even while total fuel and maintenance fall.
Compare scenarios consistently
For a cheaper-vehicle scenario, change the payment, insurance quote, depreciation estimate, fuel use, and expected maintenance rather than lowering one category and leaving the rest unchanged. For a paid-off car, remove the payment from cash flow but keep insurance, fuel, repairs, parking, tires, fees, and depreciation.