The price on a car window is not the same as the amount financed, and the monthly instalment is not the same as the cost of owning the car. A useful auto-loan comparison starts with the vehicle price, subtracts genuine upfront value such as a deposit or trade-in, adds financed charges, and then tests the resulting balance at the proposed rate and term.
Work out the amount financed first
Open the Auto Loan Calculator and enter the figures from the written quote rather than the salesperson's rounded summary. Depending on the transaction, the financed amount may include the vehicle, registration, documentation fees, taxes, warranties or other products.
Use this basic check:
Amount financed = vehicle price + financed charges − deposit − trade-in credit
If an existing car has outstanding finance, its settlement can reduce or eliminate the trade-in equity. Negative equity rolled into the new loan increases the balance even though it does not increase the value of the new car.
Compare term and interest together
A 72-month offer normally produces a smaller payment than a 48-month offer, but it can add years of interest and keep the balance above the vehicle's resale value for longer. Compare scenarios using the same amount financed:
- The shortest term that comfortably fits your budget.
- The dealer's proposed term.
- The same term with a larger deposit.
- A pre-approved bank or credit-union rate, where available.
Record the payment, total interest and total loan cost for each. Do not compare one offer that includes a warranty with another that excludes it without adjusting the financed amount.
The payment is only one ownership cost
Fuel, insurance, servicing, tyres, parking, registration and depreciation do not appear in the loan payment. A car can pass the finance calculation and still put pressure on the household budget. Add the proposed payment to the Budget Calculator and test the effect on savings. If applying for other credit soon, include it in your debt-to-income calculation.
Deposits and early repayment
A larger deposit reduces principal and usually reduces interest, but it also uses cash that may be needed for repairs or emergencies. Keep an appropriate reserve rather than putting every available amount into the purchase.
If you expect to repay early, read the contract. Some loans apply payments immediately to principal; others have prepayment conditions or front-loaded costs. The calculator cannot infer those rules.
Mistakes that distort an auto-loan estimate
- Entering the sticker price instead of the final financed balance.
- Treating a trade-in allowance as equity without subtracting its settlement.
- Ignoring optional products added to the agreement.
- Focusing on monthly payment while extending the term.
- Forgetting that a variable rate can change.
- Comparing a nominal rate with another lender's APR.
Questions people ask
How much should I put down?
There is no universal percentage. Test deposits that lower the payment without exhausting your emergency savings.
Is a longer car loan bad?
It is not automatically wrong, but it normally increases total interest and the period during which you may owe more than the car is worth.
Does the calculator include insurance and fuel?
No. Those are ownership expenses and should be budgeted separately.
Why is the dealer's payment different?
The quote may include taxes, fees, optional products, a different payment date or a different interest convention. Ask for an itemised finance disclosure and enter the exact figures.
Useful next tools
- Loan Calculator — Payment, interest and payoff for any personal or business loan.
- Auto Cover Estimator — Work out sensible liability and deductible levels.
- 50/30/20 Budget Calculator — Split take-home pay into needs, wants and savings.
- Credit Card Payoff — How long to clear a balance, and what extra payments save.
- Refinance Break-Even — See how many months until refinancing pays for itself.
This guide provides estimates and general education, not lending or purchasing advice. The signed agreement controls the actual payment schedule.
Try the tools from this guide
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