If you've ever Googled "how much can I borrow", you've probably been hit with a number that made your eyes water. $750,000. $900,000. Maybe even over a million. And you thought — really?
Here's the thing nobody tells you upfront: the number the bank says you can borrow and the number you should borrow are two very different things. Understanding the gap between those numbers is the single most important step in your home-buying journey — and it's the step most calculators skip entirely.
What "borrowing capacity" actually means
When a bank assesses your borrowing capacity, they're answering one question: "Can this person make the repayments without defaulting?" That's it. They're not asking whether you'll still be able to go on holidays, save for retirement, or handle an unexpected car repair. They just want to know you won't miss a mortgage payment.
The bank starts with your gross income — your salary before tax. They subtract your declared living expenses (or use a benchmark called HEM — Household Expenditure Measure), your existing debts, and then they stress-test the whole thing at a higher interest rate. Whatever's left determines your maximum loan size.
The result is a theoretical maximum. It's not a recommendation. It's not what you can comfortably afford. It's the ceiling — and borrowing at the ceiling is how people end up in financial stress.
The 3% serviceability buffer — and why it exists
Since 2021, the Australian Prudential Regulation Authority (APRA) has required all banks to assess your ability to repay at an interest rate at least 3 percentage points above the actual rate. So if the bank is offering you a loan at 6.5%, they're testing whether you could still make repayments at 9.5%.
This buffer exists because interest rates move. If you could barely afford repayments at today's rate, what happens when rates go up by 1%? Or 2%? The buffer is supposed to protect you — but here's the catch: even with the buffer, the maximum amount can still leave you stretched.
Why? Because the buffer protects the bank, not your lifestyle. It ensures you probably won't default. It doesn't ensure you'll still be able to save, invest, or live the life you want.
The debts that quietly destroy your borrowing power
This is where most first home buyers get blindsided. You might think your finances are in great shape — steady income, decent savings, no missed payments. But the bank sees things differently.
HECS/HELP debt
Your uni debt gets deducted from your income before the bank even starts calculating. If you earn $85,000 and have HECS, the bank treats your income as if it's roughly $81,000. That difference alone can reduce your borrowing power by $20,000–$40,000.
Credit cards
Here's the one that shocks people: banks assess your credit card at its full limit, not your balance. Got a $10,000 credit card you never use? The bank assumes you could max it out tomorrow. They'll deduct roughly $300–$450 per month from your available income — even if your balance is zero. That single unused card can cost you $30,000–$50,000 in borrowing power.
Car loans and personal loans
Monthly repayments on car loans and personal loans are deducted dollar-for-dollar from your capacity. A $500/month car loan doesn't just cost you $500 — it reduces your maximum loan by approximately $55,000–$65,000.
Buy Now Pay Later
Yes, even Afterpay counts. Lenders now factor in BNPL balances as ongoing commitments. A few hundred dollars in Afterpay might seem harmless, but it signals to the bank that you're relying on credit for everyday spending.
Why NestPath shows you two numbers
Most borrowing calculators online give you one number: the bank maximum. That's useful, but it's incomplete. It's like a restaurant telling you the most expensive thing on the menu without asking what you actually feel like eating.
NestPath shows you two numbers:
- Bank Maximum — the theoretical ceiling based on how banks assess your income, expenses, and debts using APRA's serviceability rules.
- Comfortable Borrowing — a more realistic figure that leaves you room to breathe. Room for rate rises, unexpected costs, and actually enjoying your life.
The comfortable figure typically sits around 75–80% of the bank maximum. It's the number that lets you buy a home and still sleep at night.
We also break down exactly why your number is what it is. You'll see how much your HECS costs you, what your credit card is doing to your capacity, and how your living expenses compare to the bank's benchmarks. No black boxes, no mystery — just clear, honest numbers.
What you can do right now
If you're serious about buying your first home, here are three things you can do today:
- Close unused credit cards. Call the bank, cancel them, and get written confirmation. This is the single fastest way to boost your borrowing power.
- Understand your HECS balance. You can't eliminate it overnight, but knowing how it impacts your capacity helps you plan realistically.
- Run your numbers properly. Not with a generic calculator that spits out one number — with a tool that shows you the full picture, including what you can comfortably afford.
That's exactly what we built NestPath to do.
Frequently Asked Questions
What grants are available for first home buyers in Australia in 2026?
The main grants are the First Home Owner Grant (FHOG) which varies by state from $10,000-$50,000, the First Home Guarantee allowing 5% deposit with no LMI, the First Home Super Saver Scheme for tax-effective deposit saving, and state-specific stamp duty exemptions. Most grants only apply to new builds.
Can I combine multiple first home buyer schemes?
Yes. In many cases you can stack the FHOG, First Home Guarantee, and stamp duty exemptions together. For example, a Queensland buyer could access the $30,000 FHOG plus stamp duty exemption plus no LMI through the guarantee — saving over $55,000 combined.
Do first home buyer grants apply to established homes?
The FHOG generally only applies to new or substantially renovated homes. However, stamp duty exemptions and the First Home Guarantee apply to both new and established homes in most states. Check your state's specific rules.
