Mortgage Repayment Calculator
On this page:
- What will your home loan actually cost you each month?
- How to use the calculator
- Quick repayment reference table
- What actually drives your repayments
- Fixed or variable? It changes your repayments
- The extra repayment effect
- Principal and interest vs interest-only
- Are you paying too much right now?
- What else can you calculate?
What will your home loan actually cost you each month?
That’s the question this calculator is built to answer. Plug in your loan amount, interest rate and term, and you’ll get an accurate picture of your monthly, fortnightly or weekly repayments straight away.
But repayments are only part of the story. The calculator also lets you compare what happens when you adjust your rate, change your term, or add extra payments each month. Small changes can make a surprisingly large difference over 25 or 30 years.
How to use the calculator
Enter three things: the amount you want to borrow, your interest rate and your loan term. The calculator does the rest. You can switch between repayment frequencies and toggle between principal and interest or interest-only to see how each option changes your numbers.
If you want to compare two different loan scenarios side by side, our Loan Comparison Tool is designed for exactly that.
Quick repayment reference table
Here are estimated monthly repayments for common loan sizes over a 30-year term at various interest rates. These are estimates only and don’t account for fees or rate changes over time.
| Interest Rate | $500,000 | $750,000 | $1,000,000 | $1,250,000 |
|---|---|---|---|---|
| 5% | $2,684 | $4,026 | $5,368 | $6,710 |
| 6% | $2,998 | $4,497 | $5,996 | $7,494 |
| 7% | $3,327 | $4,990 | $6,653 | $8,316 |
| 8% | $3,669 | $5,503 | $7,338 | $9,172 |
Based on principal and interest repayments over 30 years.
What actually drives your repayments
Four things determine what you’ll pay each month.
- The loan amount: Borrow more and you pay more. Pretty straightforward. But it’s also where your borrowing power comes into the picture, because what you can borrow depends on your income, expenses and existing debts.
- The interest rate: A difference of even 0.5% across a 30-year loan can add up to tens of thousands of dollars in extra interest. This is why the rate you start on matters, and why it’s worth revisiting your loan every year or two to make sure you’re not paying more than you should. We proactively review our clients’ loans and last year alone saved them $61,650 in unnecessary interest.
- The loan term: A longer term means lower monthly repayments, but more interest over the life of the loan. A 30-year loan on $600,000 at 6% will cost you roughly $250,000 more in interest than a 20-year loan on the same amount. Worth knowing before you lock anything in. And if you ever refinance, it’s worth being careful about this too – refinancing can reset your loan term to 30 years if you’re not paying attention.
- Repayment frequency: Switching from monthly to fortnightly repayments is one of the simplest things you can do to pay your loan off faster. Because you end up making 26 fortnightly payments rather than 12 monthly ones, you’re effectively squeezing in an extra month of repayments each year without really noticing.
Fixed or variable? It changes your repayments
Whether you choose a fixed or variable rate affects not just what you pay, but how predictable those payments are.
A fixed rate locks in your repayment for a set period – usually one to five years. You know exactly what’s coming out of your account each month, which makes budgeting easier. The trade-off is less flexibility. Most fixed loans limit extra repayments, and if you want to exit the loan before the fixed term ends, break costs can be significant.
A variable rate moves with the market. When the Reserve Bank cuts rates, your repayments should come down. When rates rise, they go up. Variable loans typically come with more features too: redraw facilities, offset accounts and unlimited extra repayments. These features can save you a lot of interest over time if you use them well.
Some borrowers split their loan between fixed and variable, which gives them a bit of both. We’ve written a full breakdown of how to think through this decision in our article Fixed Rate vs Variable Home Loan Rate.
The extra repayment effect
One of the most useful things this calculator shows you is what happens when you pay a little more each month. It’s not a small effect.
On a $600,000 loan at 6% over 30 years, adding just $300 extra per month knocks roughly four years off the loan and saves around $90,000 in interest. The maths is simple: every dollar you pay early reduces the principal, which reduces the interest charged on that principal, which compounds in your favour over time. Our guide to extra mortgage repayments goes deeper on this if you want to see how it plays out across different scenarios.
The catch is that not all loans allow unlimited extra repayments. Fixed-rate loans in particular often cap how much extra you can pay each year. If this matters to you, it’s an important thing to check before you commit to a loan product.
Principal and interest vs interest-only
Most home loans are principal and interest, meaning each repayment chips away at both the amount you owe and the interest on that amount. Your balance falls over time and eventually hits zero.
Interest-only loans work differently. For a set period, usually one to five years, you only pay the interest component. The balance doesn’t reduce. Repayments are lower during this period, but once it ends you’re paying principal and interest on the full original amount with fewer years remaining, which pushes monthly repayments up considerably.
Interest-only loans are common in investment strategies, but they’re not for everyone and the numbers need to stack up properly. If you’re unsure which structure fits your situation, that’s a conversation worth having with a broker before you apply.
Are you paying too much right now?
If you already have a home loan, there’s a reasonable chance you’re paying more interest than you need to. About 7 in 10 of the existing clients we review each year have room to save something, whether through a rate negotiation, a refinance to a better product, or a simple restructure.
Refinancing isn’t just about chasing the lowest rate. It can also be about repricing your existing loan without switching lenders, accessing equity, consolidating debt, or adjusting your term. There are genuine trade-offs to understand though, including the costs and risks of refinancing and whether your current equity position means you’d be up for LMI again.
If you want to run the numbers on your current loan, a Free Lending Strategy Session with one of our Geelong brokers costs you nothing and usually takes about an hour.
What else can you calculate?
This calculator handles repayment estimates, but there are a few other tools that fit alongside it depending on where you’re at:
- Borrowing Power Calculator – find out how much you might be able to borrow based on your income and expenses
- Loan Comparison Tool – compare two different loan scenarios side by side, including the impact of extra repayments
- Buying and Selling Costs Calculator – understand the full cost of buying or selling, including stamp duty and agent fees
- Home Loan Guide – if you want to learn the basics before doing anything else, this is the place to start
This calculator provides general estimates only and does not constitute financial advice. Borrowing capacity varies by lender and individual circumstances. Please speak with a licensed mortgage broker before making any borrowing decisions.