The 5 year cost of ownership for a car is the amount you spend to buy, finance, run and eventually sell it over five years—not just its sticker price. A lower-priced vehicle can cost more overall if it loses value quickly, uses more fuel, attracts higher insurance premiums or needs frequent repairs. To compare cars fairly, estimate each expense using your expected kilometres, likely financing terms and a realistic resale value. For a New Zealand estimate, include vehicle licensing, WoF costs and road user charges where they apply. The result won’t be exact, but it can show which option better fits your budget.
Start with a consistent formula for every car you’re considering:
5-year ownership cost = purchase price and buying costs + financing costs + running and ownership expenses − expected resale value
Buying costs can include compulsory charges or fees paid to complete the purchase. Financing costs are the interest and loan fees, not the loan principal on top of the purchase price. Running and ownership expenses include fuel or charging, insurance, maintenance, repairs, tyres, vehicle licensing and inspections. Subtract the amount you reasonably expect to receive when you sell or trade in the car at the end of year five.
Divide the five-year total by five to get an average annual cost, or by 60 for an average monthly cost. These averages help compare options, but they don’t predict when bills will arrive. Insurance may be paid annually, while a repair or set of tyres can create a larger one-off expense.
There are two sensible ways to include a loan. The first is to use the car’s purchase price, then add interest and loan-related fees. The second is to add your deposit and all loan repayments, then add any loan fees not already included in those repayments. Don’t add the purchase price to the full repayments: repayments already include the amount borrowed, so doing so counts the principal twice.
For a cash purchase, use the amount paid for the car and associated buying costs, with no loan interest. If a loan includes an establishment fee in the financed balance, count that fee only once. Keep the calculation separate from your monthly budget: the ownership-cost estimate measures the cost of having the car, while a cash-flow plan shows what you must pay and when.
Use the same ownership period and assumptions for each vehicle. A table helps make gaps in an estimate visible before you commit.
| Cost | How to estimate it | What can change it |
|---|---|---|
| Depreciation | Purchase value less expected resale value after five years | Condition, kilometres travelled, model demand and sale method |
| Finance | Interest and borrowing fees, or total repayments under the alternative method | Deposit, loan term, rate, fees and early repayment conditions |
| Fuel or charging | Expected distance driven multiplied by the vehicle’s real-world energy use and your cost per unit | Driving mix, load, driving style and where you refuel or charge |
| Insurance | Quotes for the cover and excess you would actually choose | Driver details, location, vehicle, cover level and claims history |
| Maintenance and repairs | Scheduled servicing, tyres and other expected work, plus a repair allowance | Age, condition, service history, kilometres and warranty coverage |
| Licensing and inspections | Expected vehicle licensing, WoF and any applicable road user charges | Vehicle type, use and requirements in force during ownership |
Depreciation is the difference between what you pay for the car and what you get back when you sell it. It is often one of the largest ownership costs, but the amount is uncertain until sale. A newer vehicle may have a higher purchase price, while a used vehicle’s lower price does not guarantee that it will retain more of its value.
Estimate resale value using comparable vehicles of a similar age, model, condition and distance travelled, and treat the result as a forecast rather than a promise. Your sale method and the car’s condition can affect the amount you receive. If you expect to sell privately, don’t base your estimate solely on trade-in values, or vice versa.
For a used car, consider how its current age, service records and condition might affect both repairs and resale. An independent inspection can help identify issues before purchase, though it cannot predict every future repair. For any vehicle, check what the warranty covers, how long it lasts and whether any conditions apply.
Estimate energy costs from how you actually plan to use the vehicle. For a petrol or diesel car, a basic calculation is:
Annual fuel use = annual kilometres ÷ 100 × real-world consumption in litres per 100 kilometres
Multiply that result by your expected cost per litre, then extend the estimate over five years. For an electric car, use expected electricity consumption per 100 kilometres and the rates you expect to pay for charging. If you will charge in more than one way, estimate each share separately rather than assuming every kilometre has the same cost.
Use a distance estimate based on your commute, regular trips and occasional longer journeys. The figure shown in a vehicle’s specifications may not match your driving conditions, so look for realistic consumption information for the specific version and use case. In New Zealand, include road user charges if they apply to the vehicle and your intended use; confirm the current requirements for the particular vehicle before finalising your estimate.
Get insurance quotes for the actual cars you’re comparing. Premiums can differ even when the vehicles have similar purchase prices, and a quote depends on details such as the driver, location, selected cover and excess. Compare like with like: a cheaper premium may reflect less cover or a higher excess, which could mean more out-of-pocket cost after a claim.
Build a maintenance estimate from the manufacturer’s service schedule and the vehicle’s condition. Include routine servicing, tyres and other wear items, as well as likely inspection costs. For a used vehicle, review its service history and ask what work is due soon. Set aside a separate repair allowance rather than assuming every car will need the same repairs or none at all.
Include vehicle licensing and WoF costs in a New Zealand estimate, and account for any other regular expenses that matter to your use, such as parking. Avoid adding optional costs you would not actually incur. If you use a vehicle for work or have unusual storage or usage needs, include the relevant expense consistently for every option.
For example, a vehicle with a lower purchase price may still be the more expensive choice if its insurance, energy use or anticipated repair costs are substantially higher. Conversely, a higher-priced option may not be better value if you won’t recover enough of that extra cost when you sell. The comparison is useful only when both cars are assessed over the same distance and period.
Some costs are easier to establish than others. A purchase offer, loan quote and insurance quote can provide specific figures, while future repairs and resale value are estimates. Don’t disguise that uncertainty by entering precise-looking numbers without a sound basis.
For the less certain items, create a lower and higher estimate. You might vary expected resale value, annual kilometres or repair spending while keeping the other assumptions unchanged. This shows whether your preferred car remains affordable under less favourable conditions. If a small change in one estimate reverses the result, treat the comparison as close rather than assuming one vehicle is clearly cheaper.
Also check whether your planned ownership period is realistic. If you might sell after three years or keep the car well beyond five, repeat the calculation for that period: depreciation, finance and maintenance can change over time. A five-year estimate is a planning tool, not a guarantee of what you will spend.
A useful estimate need not predict every bill. It should make assumptions visible, use comparable inputs and show where the biggest financial risks sit. Keep the figures in a simple spreadsheet or worksheet so you can update them when you receive a quote, inspect a vehicle or revise your expected kilometres.
Yes. Include the purchase price and relevant buying costs, then subtract the expected resale value. Add finance interest and fees separately if you’re using the purchase-price method.
Do not add the full loan repayments on top of the purchase price. Either count the purchase price plus interest and loan fees, or count your deposit and repayments, taking care not to add the same fee twice.
Use comparable vehicles as a guide, taking account of age, model, condition and kilometres. Treat the result as uncertain, and test whether the car still suits your budget if you receive less than expected.
Use your expected distance and realistic energy use to estimate fuel or charging, then include insurance, maintenance, finance, resale and any applicable vehicle charges for both. Charging access and where you expect to charge can affect the electric car’s energy-cost estimate.
Not necessarily. Your estimate may favour one vehicle, but reliability uncertainty, available cash, driving needs and the condition of a specific used car also matter. Consider whether the expected saving is large enough to justify any added cost or risk.
Before buying, compare the full five-year estimate—not just the advertised price—and keep a cautious view of resale and repair costs. A consistent calculation gives you a clearer picture of affordability and helps you choose a car whose likely expenses fit your budget.
