Loan portability: can you take your mortgage with you when you move?

You might be able to keep your loan and put it on a new home. It's called porting, and it's worth asking about if you've got a fixed rate you'd like to keep or want to avoid paying the loan out early.

Lenders also call it a substitution of security or a security swap. The security is the property your loan is secured against. Before committing to the move, compare keeping the loan with paying it out and taking a new one.

An eligible Westpac security substitution can keep your existing rate, repayments and features. You may avoid fixed-rate break costs if only the security changes and nothing else does.

That's one lender's condition, not a promise every portable loan is fee-free. A break cost is a charge that can apply when you repay or change a fixed loan early.

Start with what you want to keep, then ask what the change would cost. If your loan has several parts, get written confirmation for each. A fixed part staying put doesn't tell you what happens to another account, an offset or a guarantee.

Ask for a written list matching each loan split to the properties securing it. Don’t work this out from the account nickname or the original purpose of the borrowing. Confirm what must be repaid, released or replaced at settlement before the discharge form is lodged.

Ask for a new-loan comparison over the same remaining term. A smaller payment stretched over more years won't tell you whether the loan is cheaper. Our refinance guide explains the switching costs to include.

The new place must be acceptable security. A high purchase price doesn't guarantee the bank values it at that amount or accepts its title and property type.

The people on the loan matter too. With CommBank, you can only port the loan if the borrowers and anyone providing security stay the same.

The old security must be released at the same time as, or before, the replacement security is granted. Other lenders have their own rules.

Give your lender and conveyancer both contracts and settlement dates early. Ask what happens if one settlement slips, as well as how the plan works if both run on time.

If you sell first and buy later, ask whether cash can be temporary security. Westpac's eligible deferred-settlement option uses a term deposit for up to 6 months. Apply before selling so the term deposit can be set up.

You can't access that deposit during the gap, and normal repayments continue. Confirm eligibility and how much will be held before treating your sale proceeds as available for the next deposit or living costs.

Buying before you sell is a separate funding question. Portability approval isn't bridging finance approval. Our bridging loan guide explains that option, and our guide to upgrading to your next home compares buying first with selling first.

Macquarie requires the sale and purchase to settle on the same day, with credit assessment and approval. Allow up to 28 days. You cannot increase the facility limit through the swap, and some Macquarie loans cannot use it. We'll check your loan before you set the dates.

That is a different timing option from Westpac's eligible deferred arrangement above. If you sell first and need a gap before buying, don't assume Macquarie will hold the sale proceeds as temporary security. Confirm an alternative before signing either contract. Our Macquarie home loan review explains the wider product features.

Book a free assessment before you set the settlement dates. We can check the existing lender's portability route, any separate borrowing increase and the cost of a replacement loan. Your conveyancer can then coordinate the contracts around an approved plan.

Porting keeps an existing loan. Any extra borrowing needs its own approval, and you need to know how much sale cash will be available.

Start with net proceeds, not the sale price. Take off selling costs, any debt reduction the bank requires and money it will hold under the approved arrangement. The borrowing power calculator can give a starting estimate, but it can't approve an increase or a security swap.

If you need to borrow more for the purchase with Westpac, apply for and finalise that increase before the security swap. Increasing a fixed-rate loan can also bring break costs. Ask how the increase is assessed and whether it changes the portability proposal. Don't sign assuming the increase is part of the swap.

We'll check whether your lender accepts the new property and both settlement dates before comparing rates. If there's a gap, find out how much sale cash will be locked away and how you'll cover living costs until you buy.

We can put these questions to your existing lender, then compare porting with a new loan from our panel using the same balance and remaining term. Get written confirmation of the following:

• Can this loan be ported to this property with these borrowers and security providers?
• What happens to each loan part, linked account and guarantee?
• How much cash do I need, including money held back or debt reduction required?
• When will approval and any loan increase be finalised for the proposed settlements?

Ask your conveyancer how the settlements should be coordinated and what contractual protection is appropriate. Get lender approval and conveyancing advice before committing.

A cheaper arrangement may be little help if it can't work with your dates. Convenience alone isn't a reason to keep a loan that no longer suits you.

Ask for the cash needed under each option, as well as the rates and costs.

Keeping that $450,000 loan still leaves $450,000 of the price, plus buying costs. That money has to come from net sale proceeds, savings or extra approved borrowing. Porting doesn't fill the gap on its own.

No. Ask about the process early, but the lender still needs to consider the replacement property and proposed arrangement. A product being portable is not approval for a particular purchase.