How car loan repayments are calculated
A car loan is repaid in equal instalments that cover the interest charged since the last repayment plus a slice of the amount borrowed. The standard formula for the repayment is M = P × r ÷ (1 − (1 + r)−n), where P is the amount borrowed, r is the interest rate per repayment period (the annual rate divided by 12 for monthly repayments) and n is the number of repayments. With a balloon B due at the end, the calculator first takes off the present value of the balloon, B ÷ (1 + r)n, from the amount borrowed, because that part of the loan isn't paid down along the way.
Early in the loan most of each repayment is interest; by the end it's almost all principal. The table under the calculator ("What you still owe each year") shows that shift. If you add the establishment fee to the loan, as most lenders do, you pay interest on the fee too.
| Loan amount | 7.00% | 8.00% | 9.40% | 10.00% | 12.00% |
|---|---|---|---|---|---|
| $10,000 | $198 | $203 | $210 | $212 | $222 |
| $15,000 | $297 | $304 | $314 | $319 | $334 |
| $20,000 | $396 | $406 | $419 | $425 | $445 |
| $25,000 | $495 | $507 | $524 | $531 | $556 |
| $30,000 | $594 | $608 | $629 | $637 | $667 |
| $40,000 | $792 | $811 | $838 | $850 | $890 |
| $50,000 | $990 | $1,014 | $1,048 | $1,062 | $1,112 |
How the loan term changes the cost
Moneysmart notes car loans usually run for one to seven years. A longer term lowers each repayment but raises the total interest, and makes it more likely you'll owe more than the car is worth, because the car keeps losing value while you pay it off. Pick the shortest term whose repayment fits your budget with room to spare.
| Term | Monthly repayment | Total interest | Total repaid |
|---|---|---|---|
| 2 years | $1,376 | $3,025 | $33,025 |
| 3 years | $960 | $4,545 | $34,545 |
| 4 years | $752 | $6,109 | $36,109 |
| 5 years | $629 | $7,715 | $37,715 |
| 6 years | $547 | $9,365 | $39,365 |
| 7 years | $489 | $11,058 | $41,058 |
Weekly, fortnightly or monthly repayments
Paying more often reduces the balance slightly sooner, so it saves a little interest, but not much when the yearly total is the same. Choose the frequency that matches your pay so repayments never bounce. If your loan allows extra repayments without a fee, paying a bit more each time is what really shortens it.
| Frequency | Repayment | Total interest |
|---|---|---|
| Weekly | $144.72 | $7,627 |
| Fortnightly | $289.64 | $7,653 |
| Monthly | $628.59 | $7,715 |
Balloon payments
A balloon (or residual) is a lump sum you owe at the end of the loan. It lowers the regular repayment because you pay down less of the loan along the way, but you pay interest on the balloon for the whole term, so the total cost is higher. Moneysmart's advice is to be confident you'll have the money when it falls due. The usual ways to pay it are cash, refinancing it with a new loan (at whatever rate you can get then) or selling or trading in the car.
The risk is that the car is worth less than the balloon when it's due, leaving you to cover the difference. Check what similar cars of that age sell for before you choose a large balloon. Our guide to car loan balloon payments goes through the options when it falls due.
| Balloon | Monthly repayment | Total interest | Lump sum at the end |
|---|---|---|---|
| 0% | $629 | $7,715 | $0 |
| 10% | $589 | $8,354 | $3,000 |
| 20% | $550 | $8,992 | $6,000 |
| 30% | $511 | $9,631 | $9,000 |
| 40% | $471 | $10,269 | $12,000 |
| 50% | $432 | $10,908 | $15,000 |
Fees and the comparison rate
A lender that advertises an interest rate must also show a comparison rate, which rolls the interest rate and most fees into one figure. It has to be calculated on a set example: the regulations list six amounts and terms ($250 over 2 weeks, $1,000 over 6 months, $2,500 over 2 years, $10,000 over 3 years, $30,000 over 5 years, $150,000 over 25 years), and the lender uses the one closest to its typical loan, usually $30,000 over 5 years or $10,000 over 3 years for car loans. Government fees and charges are left out, and so are fees that may never happen, such as early repayment and late payment fees.
Because fees are mostly flat dollar amounts, they weigh much more on a small loan. The same $400 establishment fee and $10 monthly fee barely move the cost of a $50,000 loan but add several percentage points to a $5,000 one. That's why a comparison rate is only exact for its example, and why the calculator shows the cost including fees for your own loan.
| Loan | Interest rate | Cost including fees | Fees as a share of the loan |
|---|---|---|---|
| $50,000 over 5 years | 9.40% | 10.15% | 2.0% |
| $30,000 over 5 years | 9.40% | 10.64% | 3.3% |
| $10,000 over 3 years | 9.40% | 14.18% | 7.6% |
| $5,000 over 2 years | 9.40% | 21.31% | 12.8% |
Ask every lender, broker or dealer for the interest rate, the comparison rate and a list of every fee, including any broker or dealer introducer fee. Moneysmart points to an ASIC review of more than 350,000 car loans that found big differences in the fees people paid.
What the calculator leaves out
- Rate changes: a variable rate can move during the loan.
- Extra repayments, redraw and early payout fees.
- Stamp duty, registration, insurance and running costs, which you'll pay whichever way you buy.
- Add-on insurance financed into the loan. Moneysmart says it's usually poor value, and dealers must wait four days before selling it.
- Interest accrued daily rather than per period, which can shift the figure by a few cents.
Our car loans guide covers new versus used cars, dealer finance and pre-approval, and the novated lease calculator shows whether salary packaging would cost less.
Frequently asked questions
What are the repayments on a $30,000 car loan?
About $629 a month over 5 years at 9.40%, the RBA's average rate on new personal fixed-term loans in July 2026, with $7,715 in total interest. Over 3 years it's about $960 a month, and over 7 years $489. Fees and a balloon change the figure.
How much is a $40,000 car payment for 60 months?
About $838 a month at 9.40%, $811 at 8% or $850 at 10%, before fees and with no balloon. Total interest at 9.40% is about $10,287.
How much would a $30,000 car loan cost in total?
At 9.40% over 5 years you'd repay about $37,715: the $30,000 plus $7,715 in interest, before fees. Add the establishment fee and any monthly fees from your quote to get the full cost.
How is car loan interest calculated?
Interest is charged on the balance you still owe, usually calculated daily and charged at each repayment. Early repayments are mostly interest; later ones mostly principal. The calculator works this out at the repayment frequency you choose and shows the balance at the end of each year.
Does a balloon payment save money?
No. It lowers each repayment but increases the total interest, because more of the loan stays outstanding for longer. On $30,000 over 5 years at 9.40%, a 30% balloon lowers the repayment to $511 a month but adds $1,915 in interest, and you still owe $9,000 at the end.
Is it better to pay a car loan weekly or monthly?
The difference is small if the total you pay each year is the same: paying weekly saves a little interest because the balance falls sooner. What makes a real difference is paying more than the minimum, if your loan allows extra repayments without a fee.
