How a Guarantor Home Loan Works (and the LMI It Saves)

The short answer

A guarantor home loan lets a family member use the equity in their own property as extra security for your loan, so you can borrow more without a large deposit. That security pushes your effective loan-to-value ratio (LVR) down to 80% or less, and lenders generally waive Lenders Mortgage Insurance (LMI) as a result. On a typical $600,000 purchase, that can save you roughly $10,000 or more. The guarantor doesn't hand over cash. They pledge a capped slice of their home's equity, and that guarantee can usually be removed once you've paid your loan down to about 80% of the property's value.

How a guarantor home loan works

With a standard low-deposit loan, anything above 80% LVR normally triggers LMI: a one-off premium that protects the lender, not you, and rises sharply as your deposit shrinks. A guarantor home loan sidesteps this by adding a second piece of security.

Here's the mechanism most Australian lenders use:

• You provide whatever deposit you have (sometimes as little as 0–5%).
• A guarantor, usually a parent, offers a limited guarantee, secured against the equity in their own home, equal to the gap between your deposit and a full 20% deposit (plus a buffer for costs).
• Because the lender now holds security worth at least 20% of the purchase price, your effective LVR drops to 80% or lower, so no LMI is charged.

The guarantee is limited: the guarantor is only on the hook for the agreed portion, not your whole loan. Once your loan balance falls to around 80% of the property value (through repayments, extra repayments, or price growth), you can apply to release the guarantor, often within a few years. This is a genuine commitment with real risk. Per Moneysmart, a guarantor can be required to repay the guaranteed amount and may have their own home at risk if you default. Lenders require guarantors to get independent legal advice first.

Guarantor loan vs the First Home Guarantee

A government scheme can achieve a similar no-LMI outcome without putting a relative's home on the line. Under the First Home Guarantee (the Australian Government 5% Deposit Scheme, expanded from 1 October 2025), eligible first home buyers can buy with as little as a 5% deposit and pay no LMI, because the Commonwealth guarantees the gap. Income caps were removed and price caps lifted (for example, $1.5m for Sydney and $800k for the rest of NSW). Check eligibility and current caps on the official site, since a guarantor and the scheme are alternative ways to reach the same 80%-LVR, no-LMI position.

A worked example

Say you're buying a $600,000 property with a $60,000 (10%) deposit. Without help, you'd borrow $540,000 at 90% LVR.

	Without guarantor	With guarantor
Purchase price	$600,000	$600,000
Your deposit	$60,000 (10%)	$60,000
Loan amount	$540,000	$540,000
Effective LVR (with guarantee)	90%	~80%
LMI estimate	~$10,740	$0

At 90% LVR, True Loan's engine estimates LMI at roughly 1.79% of the loan, about $10,740 on a $540,000–$600,000 loan. The guarantor's pledge (covering the ~$60,000 needed to reach a 20% security position) takes the effective LVR to 80%, where LMI is $0. That's a saving of about $10,740 upfront, money that would otherwise be added to your loan or paid at settlement.

The repayment itself doesn't change much: a $540,000 loan at 6% over 30 years is around $3,238/month (a full $600,000 loan would be ~$3,597/month). The guarantee changes your upfront costs and LVR, not your interest rate or repayment formula.

Model this in True Loan

Open True Loan and set the loan and upfront-cost inputs to see the LMI difference yourself:

1. Enter the property price ($600,000) and your deposit ($60,000). True Loan shows the LMI estimate for your 90% LVR.
2. To model the guarantor outcome, increase the deposit (or reduce the loan) so the LVR shown is 80%, and the LMI line drops to $0. The difference between the two LMI figures is your saving.
3. Check the total funds required at settlement with and without LMI, including stamp duty for your state and conveyancing.
4. Want to clear the loan faster so you can release the guarantor sooner? Add an amount to the Extra repayment ($/month) input, or model a sustained Offset balance. These are two separate inputs, and you can see how each shortens the time to 80% LVR on the equity timeline.

To compare a guarantor path against a 5%-deposit First Home Guarantee path side by side, use the comparison tool; every scenario is shareable via URL.

Common questions and mistakes

Does the guarantor give me money? No. They pledge equity as security. No cash changes hands unless you default.

Is the guarantor liable for my whole loan? Usually only the limited guaranteed portion, not the full balance, but read the loan documents, as structures vary.

When can the guarantor be released? Typically once your loan is ~80% or less of the property value. Extra repayments, an offset balance, or price growth all help you get there faster.

Does a guarantee remove LMI or just reduce it? If the combined security reaches an 80% effective LVR, LMI is generally waived entirely. See how much LMI costs on a $600k loan and how much deposit you need to avoid LMI.

Is the First Home Guarantee better than a guarantor? Neither is "better" universally; they're different tools with different eligibility. See First Home Guarantee 5% deposit repayments.

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These figures are estimates generated by True Loan to help you understand and model your options. They are general information only, not financial or credit advice. Check current rules and price caps with Housing Australia / firsthomebuyers.gov.au, Moneysmart, and your state revenue office, and seek independent advice before going guarantor.