How a home loan rate lock works
A rate lock holds the fixed rate you were quoted from the time you request it until settlement, usually for 90 days, in exchange for a fee. Without it, the fixed rate that applies is whatever the lender is charging on settlement day. This guide explains when the fee is worth paying, what happens if rates fall after you lock, and what each lender publishes on fees, windows and eligibility.
- Fixed rates can move until settlement; CommBank publishes that they are subject to change until funding. A rate lock freezes today’s rate for 90 days
- Fees: NAB 0.15% of the approved limit ($900 on $600,000); BankSA 0.15% with a $500 minimum and $1,000 cap to $2 million; Bank Australia 0.10% with a $50 minimum; Great Southern Bank $600 flat
- If rates fall you get the lower rate at NAB, Bank Australia and BankSA; Easy Street also waives the fee when rates fall
- Settle after the 90 days and the rate of the day applies; NAB still charges the fee
- Not available for switches, splits, top-ups or repayment changes at CommBank; new applications only at Easy Street
WARNING: This comparison rate is true only for the example given and may not include all fees and charges. Different terms, fees, or other loan amounts might result in a different comparison rate. Comparison rates are based on a secured loan of $30,000 over 5 years for vehicle finance and $50,000 over 5 years for equipment finance, as required under the National Credit Code.
What is a rate lock?
CommBank's definition covers it: fixed rates are subject to change up until funding, and rate lock is an optional feature that allows you to lock in your reference interest rate on new fixed rate home loan applications for 90 days for a non-refundable fee, charged per fixed rate loan account. NAB describes the mechanism: it locks the interest rate of the day for up to 90 days from when the completed agreement has been received from all borrowers, and if the loan settles within those 90 days the fixed rate is the lower of the locked rate and the rate on the day of drawdown. The lock protects you against a rise between application and settlement, which on a purchase can be six to twelve weeks.
Is the fee worth paying?
Compare the fee with what a rise would cost over the fixed term. On $600,000 fixed for three years, a 0.25 percentage point increase costs about $1,500 a year and $4,500 over the term. NAB's fee on that loan is $900; Bank Australia's is $600; Great Southern Bank's is a flat $600; BankSA's is $900, within its $500 to $1,000 band. When fixed rates are being repriced upward, which lenders do in steps of 0.10 to 0.30 points, the fee pays for itself on the first move. When rates are flat or falling, you are paying for insurance you will not use, unless you are with Easy Street, which publishes that it applies the lower rate and does not charge the fee if rates fall before settlement. A broker watching the lenders' repricing is the best guide to which way the next move is likely to go.
What do lenders publish on rate lock?
Checked against each lender's published page on 20 September 2026; "Not published" means the page does not state it. Fees and policies change without notice, so confirm before relying on them.
| Lender | Fee | Window | If rates fall | Eligibility and exclusions | Other published terms |
|---|---|---|---|---|---|
| NAB | 0.15% of the approved limit, rounded to the nearest $10; $230 on $150,000 | Up to 90 days from receipt of the completed agreement from all borrowers; a further 90 days by new application in some cases | Lower of the locked rate and the drawdown rate | All new NAB fixed rate home loans; some exclusions listed on its page | Fee non-refundable once payable, debited at drawdown; if settlement falls outside 90 days the rate of the day applies and the fee is still charged; the fixed term does not change the fee |
| BankSA | 0.15% of the loan amount, minimum $500, capped at $1,000 for loans up to $2 million; 0.15% uncapped above $2 million | Up to 90 days | Lower rate given at settlement | Apply through a Home Finance Manager or broker | Without a lock, the fixed rate is the rate at settlement or when the fixed period starts |
| Bank Australia | 0.10% of the total fixed loan amount, minimum $50; $300 on $300,000; charged per fixed split with a lock | 90 days from rate lock acceptance | Lower locked-in rate applies | Approved home loan applications | Fee includes any capitalised LMI in the fixed amount ($204.50 on $200,000 plus $4,500 LMI) |
| Great Southern Bank | One-off $600 per fixed rate loan locked | 90 days; must settle within the period | Not published | New fixed loans from $100,000, or switching or restructuring existing loans | On expiry of the fixed period the loan reverts to the Basic Variable Reference Rate |
| Easy Street | Charged at settlement, deducted from loan proceeds; amount not stated on the page | 90 days from the day the full application is submitted | Lower rate applied and no fee charged | New applications only, not internal switches; any fixed owner-occupier or investment loan | One fee when split between two fixed products on one property; a fee per loan on different properties; no fee if you switch products before settlement |
| CommBank | Non-refundable fee per fixed rate loan account; amount not stated on the support page | 90 days | Not published | New fixed rate home and investment loan applications; not Green Loan, switching, splitting, top-ups, purpose transfers, repayment changes or Home Seeker applications | Request any time before loan documents are issued; locks the rate on the date consent is received from all applicants; purchases need a signed contract of sale first |
How to use it well
Ask at application, not after approval: Easy Street locks the rate current on the day the full application is submitted, CommBank needs the request before documents are issued, and NAB's clock starts when every borrower has signed the consent. Confirm the settlement date fits inside the window, because at NAB a settlement outside 90 days gets the rate of the day and still pays the fee. On a split loan, lock only the fixed split, and check whether the fee is per split (Bank Australia) or per property (Easy Street). And remember that a rate lock is not the same as a pre-approval: a pre-approval says the lender will lend, a rate lock says at what fixed rate, and neither guarantees the other.
Rate lock and the fixed-rate decision
A lock is only useful if fixing is right in the first place. The fixed rate guide covers when a fixed rate makes sense, and the break costs guide covers what it costs to leave one early, which is the risk the lock does not remove. A broker will quote the fixed and variable options across lenders with and without a lock, and Your Finance Guide refers you to one licensed broker partner for that; we do not lend or assess applications ourselves.
Fixed rate guides
Fixing, breaking, splitting and the rates themselves.
Rate lock FAQs
Is a rate lock fee worth it?
What does rate lock mean on a mortgage?
How long does a rate lock last?
What if rates fall after I lock?
How much is a rate lock fee?
Can I rate lock a split loan or a refinance?
When do I have to decide?
Lock the rate before settlement, not after
Tell us your settlement date and the loan you are fixing, and we refer you to one licensed broker partner who prices the rate lock against the likely move and requests it at application. Free for borrowers, no obligation.