Mortgage and refinance analyser
Repayments, interest and fees on a home loan, what an offset account or extra repayments save, and whether moving to a new loan pays once the costs of switching are counted.
Results
A worked example from the inputs shown. With JavaScript switched on, the results change as you change the inputs.
Repayment, a month
$5,562.20
Principal and interest
Total interest
$1,122,391
Over 30 years
Total repaid, with fees
$2,002,391
Repayments over the life of the loan
Loan to value ratio
80.0%
Deposit or equity $220,000
Paid off in
30 years
Around November 2056
Effective annual cost
6.70%
The yearly rate, compounded monthly
Interest for each dollar borrowed
$1.28
Over the life of the loan
Borrowing $880,000 at 6.50% over 30 years, the monthly repayment is $5,562.20. Over the life of the loan the interest comes to $1,122,391, or $1.28 for every dollar borrowed.
The loan is 80.0% of the property value. Lenders set their own limits and conditions, and this is not a measure of whether a lender would approve the loan.
Show the figures
| Year | Balance owed |
|---|---|
| 0 | $880k |
| 1 | $870k |
| 2 | $860k |
| 3 | $848k |
| 4 | $837k |
| 5 | $824k |
| 6 | $810k |
| 7 | $796k |
| 8 | $780k |
| 9 | $764k |
| 10 | $746k |
| 11 | $727k |
| 12 | $707k |
| 13 | $686k |
| 14 | $663k |
| 15 | $639k |
| 16 | $613k |
| 17 | $585k |
| 18 | $555k |
| 19 | $524k |
| 20 | $490k |
| 21 | $454k |
| 22 | $416k |
| 23 | $375k |
| 24 | $331k |
| 25 | $284k |
| 26 | $235k |
| 27 | $181k |
| 28 | $125k |
| 29 | $64k |
| 30 | $0 |
Show the figures
| Year | Interest | Principal |
|---|---|---|
| 1 | $57k | $9.8k |
| 2 | $56k | $10k |
| 3 | $56k | $11k |
| 4 | $55k | $12k |
| 5 | $54k | $13k |
| 6 | $53k | $14k |
| 7 | $52k | $15k |
| 8 | $51k | $15k |
| 9 | $50k | $17k |
| 10 | $49k | $18k |
| 11 | $48k | $19k |
| 12 | $47k | $20k |
| 13 | $45k | $21k |
| 14 | $44k | $23k |
| 15 | $42k | $24k |
| 16 | $41k | $26k |
| 17 | $39k | $28k |
| 18 | $37k | $30k |
| 19 | $35k | $32k |
| 20 | $33k | $34k |
| 21 | $31k | $36k |
| 22 | $28k | $38k |
| 23 | $26k | $41k |
| 24 | $23k | $44k |
| 25 | $20k | $47k |
| 26 | $17k | $50k |
| 27 | $14k | $53k |
| 28 | $10k | $57k |
| 29 | $6.3k | $60k |
| 30 | $2.3k | $64k |
- Principal and interest throughout
- 5 years interest only, then principal and interest
Show the figures
| Year | Principal and interest throughout | 5 years interest only, then principal and interest |
|---|---|---|
| 0 | $880k | $880k |
| 1 | $870k | $880k |
| 2 | $860k | $880k |
| 3 | $848k | $880k |
| 4 | $837k | $880k |
| 5 | $824k | $880k |
| 6 | $810k | $865k |
| 7 | $796k | $850k |
| 8 | $780k | $833k |
| 9 | $764k | $816k |
| 10 | $746k | $797k |
| 11 | $727k | $777k |
| 12 | $707k | $755k |
| 13 | $686k | $733k |
| 14 | $663k | $708k |
| 15 | $639k | $682k |
| 16 | $613k | $654k |
| 17 | $585k | $625k |
| 18 | $555k | $593k |
| 19 | $524k | $559k |
| 20 | $490k | $523k |
| 21 | $454k | $485k |
| 22 | $416k | $444k |
| 23 | $375k | $400k |
| 24 | $331k | $353k |
| 25 | $284k | $304k |
| 26 | $235k | $251k |
| 27 | $181k | $194k |
| 28 | $125k | $133k |
| 29 | $64k | $69k |
| 30 | $0 | $0 |
Scenarios
Keep the base case and try other assumptions beside it. Each scenario starts from the base case and keeps only the inputs you change in it.
Year by year30 years
| Year | Repayments | Interest | Principal | Fees | Balance at year end |
|---|---|---|---|---|---|
| 1 | $66,746 | $56,910 | $9,836 | $0 | $870,164 |
| 2 | $66,746 | $56,252 | $10,495 | $0 | $859,669 |
| 3 | $66,746 | $55,549 | $11,198 | $0 | $848,472 |
| 4 | $66,746 | $54,799 | $11,947 | $0 | $836,524 |
| 5 | $66,746 | $53,999 | $12,748 | $0 | $823,777 |
| 6 | $66,746 | $53,145 | $13,601 | $0 | $810,175 |
| 7 | $66,746 | $52,234 | $14,512 | $0 | $795,663 |
| 8 | $66,746 | $51,262 | $15,484 | $0 | $780,179 |
| 9 | $66,746 | $50,225 | $16,521 | $0 | $763,658 |
| 10 | $66,746 | $49,119 | $17,628 | $0 | $746,030 |
| 11 | $66,746 | $47,938 | $18,808 | $0 | $727,222 |
| 12 | $66,746 | $46,679 | $20,068 | $0 | $707,154 |
| 13 | $66,746 | $45,335 | $21,412 | $0 | $685,742 |
| 14 | $66,746 | $43,901 | $22,846 | $0 | $662,896 |
| 15 | $66,746 | $42,371 | $24,376 | $0 | $638,520 |
| 16 | $66,746 | $40,738 | $26,008 | $0 | $612,512 |
| 17 | $66,746 | $38,996 | $27,750 | $0 | $584,762 |
| 18 | $66,746 | $37,138 | $29,609 | $0 | $555,153 |
| 19 | $66,746 | $35,155 | $31,592 | $0 | $523,562 |
| 20 | $66,746 | $33,039 | $33,707 | $0 | $489,854 |
| 21 | $66,746 | $30,782 | $35,965 | $0 | $453,890 |
| 22 | $66,746 | $28,373 | $38,373 | $0 | $415,516 |
| 23 | $66,746 | $25,803 | $40,943 | $0 | $374,573 |
| 24 | $66,746 | $23,061 | $43,685 | $0 | $330,888 |
| 25 | $66,746 | $20,135 | $46,611 | $0 | $284,277 |
| 26 | $66,746 | $17,014 | $49,733 | $0 | $234,544 |
| 27 | $66,746 | $13,683 | $53,063 | $0 | $181,481 |
| 28 | $66,746 | $10,129 | $56,617 | $0 | $124,863 |
| 29 | $66,746 | $6,338 | $60,409 | $0 | $64,455 |
| 30 | $66,746 | $2,292 | $64,455 | $0 | $0 |
| Total | $2,002,391 | $1,122,391 | $880,000 | $0 | $0 |
Interest only against principal and interest
| Principal and interest | 5 years interest only first | |
|---|---|---|
| Repayment at first, a month | $5,562.20 | $4,766.67 |
| Repayment after the interest only years | $5,562.20 | $5,941.82 |
| Total interest | $1,122,391 | $1,188,547 |
| Total repaid | $2,002,391 | $2,068,547 |
An illustration: your loan above is principal and interest. Both use the same rate and term, without extra repayments or an offset.
The full schedule, repayment by repayment, is in the downloads.
Download
The inputs, results and schedules of the scenario on screen. Files are made in your browser; nothing is sent anywhere.
What it does
The Mortgage tab works out the repayment on a home loan and what the loan costs over its life: the interest, the fees and when it is paid off. It shows how much an offset account or extra repayments save, and what an interest only period costs against principal and interest from the start. Professional mode adds a fixed rate period, future rate changes, fees and one-off repayments.
The Refinance tab compares the loan you have with a new one. It counts the costs of switching and shows the repayment change, when the interest saved covers those costs, and the saving over the years you choose. It also tells you when a lower repayment comes from a longer term rather than a lower rate.
Understanding your results
- Repayment
- What is due each month, fortnight or week. On an interest only loan it is the interest alone, and it rises when principal repayments begin. Extra repayments you enter are included.
- Total interest
- All the interest charged until the loan is repaid. It is usually the largest cost of a home loan and the one most changed by the rate, the term and paying early.
- Loan to value ratio
- The loan as a share of the property's value. Lenders use it to set limits and to decide whether lenders mortgage insurance applies. The thresholds and prices are each lender's own.
- Interest saved
- The difference between the loan as entered and the same loan with no extra repayments and no offset. An offset saves interest without paying the loan down, so the money stays available.
- Effective annual cost
- The yearly rate that includes fees as well as interest. It is not the comparison rate lenders must publish, which is set on a standard loan of $150,000 over 25 years.
- Refinance saving and break-even
- The interest the new loan saves, less the costs of switching, over the period compared. Break-even is when the interest saved first covers those costs.
The method
How this is calculated
The repayment. A loan of P at a yearly rate r, repaid f times a year over n repayments, has a periodic rate i = r / f and a level repayment
S = P × i / (1 − (1 + i)^−n)
or P / n when the rate is zero. Monthly repayments use f = 12, fortnightly 26 and weekly 52, and interest compounds at that frequency.
Each repayment. Interest for the period is the balance owing, less any offset balance, times i. The repayment pays that interest first; the rest reduces the balance. The last repayment is only what is still owed.
Rate changes and fixed periods. When the rate changes, the repayment is worked out again so the loan is still repaid by the end of its term. A fixed period is a rate change to the rate after it.
Extra repayments and offset. The scheduled repayment follows the loan as contracted, without extra repayments or the offset. Both therefore shorten the loan rather than lower the repayment, which is how most Australian lenders apply them.
Interest only. During the interest only period the repayment is the interest charged. Principal and interest repayments then clear the loan over the rest of the term.
Fees and the effective cost. Upfront fees are paid at the start and the ongoing fee each month the loan is outstanding. The effective annual cost is the yearly rate at which the amount borrowed, less upfront fees, equals the present value of every repayment and fee.
Refinancing. Both loans are principal and interest at their rates. The saving to any date is the current loan's interest to that date, less the new loan's interest, less the costs of switching. This is the same as comparing what each loan would have cost by then, counting repayments made and the balance still owed, so a lower repayment from a longer term is not counted as a saving.
Precision. Calculations keep full precision and round only for display. A lender works out interest daily on each day's balance and charges it monthly, rounds to the cent and sets its own repayment dates, so its schedule will differ from this one by small amounts.
The full method, with every convention, is in How the tools work.
Assumptions and limitations
The default figures are an illustration: a property of $1.1 million with a loan of 80% of its value at 6.50% a year over 30 years. The rate is our assumption, not a market rate or a lender's offer; when we set it, in October 2026, the Reserve Bank's cash rate was 4.60%, and the Bank publishes the average rates lenders charge each month on its lenders' interest rates page. Use the rate and fees you have been quoted.
The tool leaves out lenders mortgage insurance, stamp duty and other purchase costs, and any tax effects, which depend on the lender, the state and your circumstances. Enter known costs as upfront fees. Offset accounts are taken to offset the full balance. Some lenders recalculate repayments differently after extra repayments or rate changes.
The results are estimates for general information. They are not an offer of credit, credit assistance or financial advice, and they do not take into account your objectives, financial situation or needs. They do not show whether a lender would approve a loan; lenders apply their own tests.
Learn more
- The Australian home loan, explained: repayments, interest only, fixed rates, offset, redraw, LMI and the lending tests.
- How lending works: what an interest rate pays for and how the cash rate reaches borrowers.
- Credit conditions in 2026: rates, borrowing power and refinancing.
- Moneysmart's mortgage calculator, from ASIC.
- The Reserve Bank's cash rate target.