Porting a mortgage UK: can you take your deal with you?

If you've found your next home but you're tied into a fixed-rate deal, porting a mortgage UK lenders allow could help you take your existing rate with you, rather than paying an early repayment charge that can run into thousands of pounds. Porting means transferring your current mortgage deal, not the loan itself, to a new property with the same lender.

Porting isn't a transfer of the loan - it's a transfer of the mortgage product. You close your existing mortgage and take out a new one with the same lender, on the same terms, secured against your new property. This is different from remortgaging with a new lender, where you switch lender entirely and start fresh, usually to access a different deal or release equity.

Not every mortgage is portable, and porting isn't automatic even if your product allows it. Your lender will reassess your income, credit history, and the new property before agreeing, so it's worth checking your mortgage offer or terms and conditions before you get too far into planning your move.

The process follows the same broad shape as a new mortgage application, but because you're staying with your existing lender, some of the underwriting can move a little faster. Here's what typically happens once you decide to move.

Porting isn't automatically the right choice just because it's available. Here's how the main advantages stack up against the trade-offs.

If your current deal is well below what's currently available and your early repayment charge would be substantial, porting is usually worth exploring first. If the gap is small, or your circumstances have changed since you took out the mortgage, it's worth arranging to speak to a remortgage advisor who can weigh up whether switching lender makes more sense for you.

If your new home costs more than your current property, you can usually port the existing balance and add a top-up loan for the difference. The two amounts are treated as separate products, even though they sit on one mortgage account.

As an illustrative example, say your current mortgage balance is £150,000 on a fixed deal, and your new home costs £275,000. You'd port the £150,000 on your existing terms, and apply for an additional £125,000 as a new product at whatever your lender is offering at the time. Your monthly payment becomes a combination of both parts, so it's worth asking your advisor to talk you through what that looks like before you commit, since actual figures depend on your circumstances and what's available when you apply.

The top-up portion will usually come with its own tie-in period and its own early repayment charge, separate from the ported part. The two products can also have different end dates, which is easy to overlook when you're focused on the property purchase itself. Flagging this to your advisor early means you go in with your eyes open rather than being surprised later.

If your new home costs less than your outstanding mortgage balance, you can't always port the full amount. As an illustrative example, say your existing balance is £200,000 but your new property is worth £150,000 - the £50,000 shortfall is effectively repaid early, and that portion is likely to trigger an early repayment charge under your original mortgage offer.

Whether porting still makes sense in this scenario depends on the size of that charge compared with what you're saving elsewhere, so it's worth checking the early repayment charge schedule in your original mortgage offer, or asking your lender directly, before you commit to a smaller property.

Your home may be repossessed if you do not keep up repayments on your mortgage or any other debt secured on it, so it's worth being realistic about affordability on the smaller property too, not just the figures on paper.

Yes. Porting still means reapplying for a mortgage, so your lender reassesses your income, credit history, and the new property from scratch. Being accepted for the original loan doesn't guarantee approval for the ported version.

Common reasons a lender might refuse to port a mortgage include:

• Your income has fallen, or your outgoings have increased, since your original application
• You've moved into self-employment and don't yet have two years of accounts
• The new property needs a higher loan-to-value than your lender's current policy allows
• The property type doesn't meet lending criteria, for example ex-local authority flats, high-rise buildings, or non-standard construction
• Your credit profile has deteriorated since you took out the mortgage

If your lender declines to port your mortgage, you still have options. You could pay the early repayment charge and look at remortgaging with a new lender, explore bad credit mortgage options if your credit history is the sticking point, or in some cases use a bridging loan to cover a short gap while you sort out a longer-term solution, though this tends to be an expensive last resort. Your home may be repossessed if you do not keep up repayments on your mortgage or any other debt secured on it, so any borrowing used to bridge a gap needs careful thought before you commit.

If you're worried about how a change in circumstances, such as a change in income or a new credit issue, might affect your ability to port or remortgage, free and impartial guidance is available from MoneyHelper on 0800 138 7777.

Because porting means a fresh application, you'll need much the same paperwork as you did for your original mortgage. Having everything ready before you apply can help avoid delays at the underwriting stage.

Porting and remortgaging solve different problems, and the cheaper option depends on your early repayment charge, your current deal, and what else is available. Here's how they compare.

Porting tends to work out cheaper when your early repayment charge is high and your current deal is significantly better than what else is on offer. Remortgaging tends to make more sense when the gap is small, or when a different lender can offer something your current one can't, such as a higher loan-to-value or more flexible criteria. It's worth speaking to a broker who compares a wide range of lenders before deciding, rather than relying on either your existing lender or a single new one for the full picture. You can check any firm's authorisation on the Financial Conduct Authority register.

Most porting applications take between six and twelve weeks from application to completion, though this varies with your chain and how quickly your lender can process the paperwork. A rough breakdown looks like this:

• Decision in principle: one to five days
• Valuation on the new property: one to two weeks
• Full underwriting and affordability reassessment: one to three weeks
• Legal work and conveyancing: four to eight weeks, often running alongside underwriting

Most lenders also build in a grace period between selling your current home and completing on the new one, typically somewhere between 30 and 90 days for high street lenders, and up to 180 days with some building societies. This matters if your onward purchase falls through or gets delayed, since it affects how much flexibility you have before your ported deal needs to complete. Check the specific window with your lender rather than assuming a standard figure applies.