🏠 Home Loan Calculator
Enter your loan details to estimate repayments and see how extra payments change things.
Results
Fees breakdown
Balance by year
| Year | Principal paid | Interest paid | Balance |
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Why use this calculator?
A home loan is the largest thing most people ever pay for, and the repayment on its own says very little about what it costs: two loans with the same repayment can be tens of thousands of dollars apart once the term and the interest are counted in. This calculator puts the whole loan in front of you — the repayment, the interest, the fees, and the year the balance finally reaches zero. It is also the quickest way to answer the two questions worth asking before signing anything: what would paying a little extra each period actually save, and is the shorter term worth the higher repayment?
Things the repayment figure doesn’t say
A few facts about home loans that the repayment figure cannot show:
- The word mortgage is a translation of the Old French mort gage, a “dead pledge”, because the pledge died one of two ways: the debt was paid, or the property was lost. Medieval lawyers drew the contrast with the “living gage”, where the income from the land paid the debt down as it went.
- On this page’s default loan — $500,000 at 6% over 30 years — the first repayment of $2,997.75 is $2,500 of interest and $497.75 of loan, so 83% of the first month buys nothing but time. Across the whole term the interest comes to $579,191, which is $1.16 of interest for every dollar borrowed.
- The interest is heaviest at the start, which is why small extras early are worth more than the same money later. An extra $100 a month on that loan saves $57,325 in interest and finishes it 2 years 6 months early, and the extras themselves only come to $33,000.
How does this calculator work?
The repayment comes from the standard amortisation formula. The yearly rate is divided by the number of repayments in a year, the term becomes the number of repayments, and the two give the fixed payment that clears the loan exactly at the end:
M = P × r ÷ (1 − (1 + r)^−n)
where P is what you borrow, r is the rate for one period (the yearly rate ÷ 100 ÷ repayments per year) and n is the number of repayments (years × repayments per year).
From there the loan is walked through period by period rather than trusted to the formula, which is what lets extra repayments and fees mean something:
- Each period the interest is the balance × r, and whatever is left of the repayment pays the balance down.
- An extra repayment goes straight onto the balance, so it saves the interest that money would have been charged, and because the balance falls faster the loan finishes sooner.
- Weekly repayments are the monthly repayment ÷ 4 and fortnightly ÷ 2, which is how most lenders work them out. That is 13 monthly payments a year instead of 12, so the loan is paid off sooner. The second option recalculates the repayment for the frequency instead, which leaves the term the same as monthly.
- Fees are added on top of the interest: the establishment and discharge fees once each, and the account keeping fee for every month the loan is open. The saved-by-extras figure counts the interest it saves plus the account fees you stop paying by finishing earlier.
Frequently asked questions
Why is my repayment different from what my lender quotes?
Nearly every lender rounds the repayment up to the nearest dollar or cent and charges interest on the daily balance, and some collect fees with the repayment. This page works with an exact repayment and interest charged once per period, so a few dollars either way is normal. The total interest and the total cost are the figures worth comparing, not the last dollar of the repayment.
Does paying weekly or fortnightly really save money?
With the lender method, yes. Half the monthly repayment paid fortnightly, or a quarter of it weekly, comes to 13 monthly payments a year rather than 12, and that extra payment is what shortens the loan. If repayments are recalculated for the frequency instead, the loan runs for the same term as monthly and the saving disappears. The note under the results tells you which of the two you are looking at.
Do extra repayments lower my repayment or shorten the loan?
They shorten the loan here. The calculator holds the agreed repayment and adds the extra on top of it, which is what happens when you leave the repayment alone and pay more in. Many lenders will instead recalculate a smaller repayment if you ask them to, and the interest saved is smaller that way.
Does it include stamp duty, insurance or council rates?
No. Only the loan is here: the interest and the three fees you can type in. Upfront costs such as stamp duty, transfer fees and lenders mortgage insurance are paid before the loan starts, and rates, insurance and maintenance keep coming afterwards, so they belong in your own picture rather than in this one.
Where does an offset account fit in?
It does not appear on this page. The Offset Account Calculator takes the same loan and works out what keeping money in an offset saves you in interest and time, using the same repayment.
Is the interest rate fixed for the whole term?
Yes — the arithmetic uses one rate for the life of the loan, which is what a fixed rate does. A variable loan moves with the market, so try the rate a whole percentage point higher and then a point lower to see the range you are really exposed to.
What does the share button actually send?
The sentence on the result card and a link to this page, and nothing else. The site sends nothing anywhere by itself: the button hands that sentence to your own device’s share sheet, or puts it on your clipboard when the device has no share sheet to offer. What you do with it after that is between you and whichever app you picked.