Worked Examples and Checklists
Personal loan repayments worked example: $20,000 over 3, 5 and 7 years
How Australian personal loan repayments are calculated, with a $20,000 worked example over three, five and seven years, a year-by-year balance table and the effect of rate changes.
On an illustrative $20,000 personal loan at 11.5% a year, monthly repayments are about $660 over three years, $440 over five years and $348 over seven years. The longer term cuts the repayment by almost half but raises total interest from about $3,740 to about $9,210. Repayments on most Australian personal loans are worked out with the standard amortisation formula, so each payment covers that month's interest first and the rest reduces the balance. Use the repayment calculator to repeat these numbers with your own rate, term and fees.
This guide is part of the personal loan requirements guide. All figures are illustrative, not lender offers.
The formula
For a loan of P dollars at an annual rate of R%, repaid monthly over n months:
- monthly rate r = R ÷ 100 ÷ 12
- repayment = P × r ÷ (1 − (1 + r)^−n)
For $20,000 at 11.5% over 60 months:
- r = 0.115 ÷ 12 = 0.009583
- (1 + r)^−60 ≈ 0.5643
- repayment = 20,000 × 0.009583 ÷ (1 − 0.5643) ≈ 191.67 ÷ 0.4357 ≈ $439.85
In the first month, interest is $20,000 × 0.009583 ≈ $191.67, so about $248 of the first repayment reduces the balance. As the balance falls, the interest share shrinks and more of each repayment goes to principal.
Comparing terms
| Term | Monthly repayment | Total repaid | Total interest |
|---|---|---|---|
| 3 years (36 months) | about $659.52 | about $23,743 | about $3,743 |
| 5 years (60 months) | about $439.85 | about $26,391 | about $6,391 |
| 7 years (84 months) | about $347.73 | about $29,209 | about $9,209 |
Going from three to seven years lowers the repayment by about $312 a month but costs about $5,470 more in interest. Add any establishment and monthly fees on top; see fees vs rate.
Year-by-year balance on the five-year loan
| End of year | Balance owing (approx.) | Paid off during the year |
|---|---|---|
| 0 (start) | $20,000 | – |
| 1 | $16,860 | $3,140 |
| 2 | $13,339 | $3,521 |
| 3 | $9,390 | $3,949 |
| 4 | $4,964 | $4,426 |
| 5 | $0 | $4,964 |
After two years, with 40% of the term gone, you still owe about two thirds of the loan. This matters if you plan to sell a car bought with the loan, or to refinance: the balance falls slowly at first.
How the rate changes the repayment
Keeping $20,000 over five years:
| Rate (illustrative) | Monthly repayment | Total interest |
|---|---|---|
| 9.5% | about $420.04 | about $5,202 |
| 11.5% | about $439.85 | about $6,391 |
| 13.5% | about $460.20 | about $7,612 |
Each 2 percentage points changes the repayment by about $20 a month and total interest by about $1,200 on this loan. The lender's risk-based pricing — what it charges you after assessment — therefore matters as much as the term. See credit scores.
Weekly, fortnightly or monthly?
Many lenders let you choose the repayment frequency.
- Equivalent frequency: if the lender simply divides the monthly figure (for example, monthly × 12 ÷ 26 for fortnightly), you pay slightly earlier in each month and save a little interest.
- Half-monthly fortnightly: if you pay half the monthly repayment every fortnight, you make 26 half-payments a year — the equivalent of 13 monthly repayments — and the loan finishes earlier.
On the five-year loan, paying $219.93 every fortnight (half of $439.85) adds roughly one extra monthly repayment each year. Check the contract: some lenders recalculate fortnightly repayments differently. Extra repayments are covered in paying off a personal loan early.
Checking a lender's figures
Before signing, compare the lender's figures with your own:
- The financial table should show the amount of credit, annual percentage rate, repayment amount and frequency, and total amounts where they can be worked out.
- Recalculate the repayment with the calculator. If it is higher than expected, ask whether fees or insurance premiums have been added to the loan.
- Check whether the establishment fee is included in the amount of credit.
- Confirm the first repayment date. A longer first period means more interest in the first repayment.
Frequently asked questions
Why is my first repayment different?
The first period may be longer or shorter than a normal month, depending on when the loan settles and when the first repayment is due. Lenders sometimes adjust the first or last repayment.
Do personal loans calculate interest daily?
Many lenders calculate interest daily on the outstanding balance and charge it monthly. The monthly formula above gives a very close estimate.
Is a longer term ever the better choice?
A longer term can make the loan affordable and leave a buffer in your budget, which can reduce the risk of missed payments. If the loan allows extra repayments without a fee, you can choose a longer term and pay it down faster when you can.
What is a balloon payment?
A balloon is a lump sum due at the end of the loan, common in car finance. It lowers regular repayments but leaves a large final payment and increases total interest. The calculator here does not model balloons.
Sources and where to check
- ASIC Moneysmart — personal loan calculator and guides
- Federal Register of Legislation — National Credit Code disclosure requirements
- ASIC — credit contract information
