// Source citations for the factual claims in this guide (kept out of the // rendered tree: flow-level MDX comments break Next scroll-on-navigation). export const sources = [ "Porting mechanics verified against HSBC UK, 'Port your HSBC mortgage to your new home', https://www.hsbc.co.uk/mortgages/existing-customers/move/, retrieved 2026-06-12: porting requires a new mortgage application meeting the lender's affordability criteria with the new property meeting lending and valuation criteria; additional borrowing goes on a new rate alongside the ported rate; if sale and purchase are separated, the ERC paid on redemption is refunded when the new mortgage completes within 6 months; borrowing less can trigger an ERC on the amount not taken across (beyond the overpayment allowance).", "ERC conventions verified against MoneySuperMarket, 'Mortgage early repayment charges explained', https://www.moneysupermarket.com/mortgages/early-repayment-charges/, retrieved 2026-06-12: ERCs range from 1% to 5% of the remaining loan and the percentage tends to decrease each year of the deal; portable mortgages may transfer without an ERC, though downsizing and reducing the loan can still trigger one.", "Affordability re-check context from site/lib/mortgage-affordability.ts (assumptions verified in-file 2026-06-10): lenders commonly offer around 4 to 4.5 times income, and FCA rules (MCOB 11.6.18R) require affordability to be tested against at least a 1 percentage point rate rise, with many lenders stressing harder.", "Worked comparison computed with the amortisation formulas in site/lib/remortgage.ts (monthlyPayment, balanceAfter, and the costOverDeal convention of payments + upfront costs + closing balance minus opening balance). Port case: £200,000 at 4.2% over 240 months for the 18-month window costs £12,309 (£1,233/mo) plus a £40,000 top-up at 5.5% costing £3,234 (£275/mo), total £15,543. Break case: £240,000 at 5.5% plus a £4,000 ERC costs £23,404 (£1,651/mo). Reversed case over a 24-month window: £200,000 at 6.0% plus £40,000 at 4.5% costs £26,871 versus £240,000 at 4.5% plus £4,000 ERC costing £24,942.", ];

Guide · 5 minute read · Updated 2 Jul 2026

Can I port my mortgage to a new house?

Usually yes, if your deal is portable and you still pass the lender's checks. But porting moves your interest rate to a new loan; it is a full re-application, not a transfer, and any extra borrowing lands on a second, current-market rate.

What porting actually moves

A portable mortgage lets you take your current deal's rate, and its remaining fixed period, to the next property. What it does not do is move the loan itself. Legally you repay the old mortgage when you sell and take out a brand new one on the new house; the lender simply agrees to price part of it at your old rate and waive or refund the early repayment charge on that slice.

That distinction matters because everything about the new loan is decided fresh: the amount, the property valuation, and crucially whether the lender still thinks you can afford it.

The re-application nobody warns you about

Porting means a new application against the lender's current criteria. HSBC, for example, states plainly that you must complete a new mortgage application, meet its affordability criteria, and the new property must pass its lending and valuation rules. This is where ports most often fail: your circumstances are compared to today's rules, not the ones you were approved under.

Common reasons people who comfortably hold a mortgage get refused a port for the same amount: income dropped or became self-employed, a partner stopped working, new childcare costs or loan repayments, or the lender's stress test got tougher (FCA rules require testing against at least a 1 percentage point rate rise, and many lenders stress harder). Paying your current mortgage flawlessly for years counts for surprisingly little. Run your numbers through our mortgage affordability calculator before you fall in love with a house, using your situation as it is now.

Borrowing more means a second rate

If the new house costs more, the extra borrowing cannot join your old rate. It goes on a separate product at today's prices, so you end up with a split mortgage: the ported slice at your old rate, the top-up at a current rate, often with its own fees and its own end date. Misaligned end dates are a real nuisance later, because when one deal ends you remortgage that slice while the other may still carry an early repayment charge.

Borrowing less is not free either. Reduce the loan beyond your annual overpayment allowance and most lenders charge the ERC on the part you leave behind.

Porting versus paying the ERC: a worked comparison

Say you owe £200,000 at a fixed 4.2% with 18 months left, 20 years remaining on the term, and you need £240,000 for the new house. New deals are priced around 5.5%, and your ERC is 2% (£4,000). ERCs typically run from 1% to 5% of the balance, stepping down each year of the deal.

Port: keep £200,000 at 4.2% (£1,233 a month) and take a £40,000 top-up at 5.5% (£275 a month). Total cost in interest over those 18 months is about £15,543.

Break: pay the £4,000 ERC and put the whole £240,000 on 5.5% (£1,651 a month). Cost over the same window is about £23,404.

Porting wins by roughly £7,900 here, because you keep a below-market rate on the big slice and pay no ERC. As a rule of thumb, when your existing rate is lower than today's rates, porting is hard to beat.

When breaking the fix wins

Flip the rates and the answer flips. If you are fixed at 6.0% with two years left and new deals are at 4.5%, porting £200,000 plus a £40,000 top-up costs about £26,871 over those 24 months, while paying the £4,000 ERC and putting £240,000 on 4.5% costs about £24,942. Breaking saves nearly £2,000, and you get one clean rate with one end date. The smaller the ERC and the bigger the rate gap, the stronger the case; our remortgage calculator does this break-even sum with your own figures, including the ERC and arrangement fees.

Timing, and what to do if the port is refused

If you sell before you buy, you normally pay the ERC at redemption and the lender refunds it when the new mortgage completes within its porting window (six months at HSBC; some lenders allow only three, so check yours). Miss the window and the ERC is gone for good.

If your own lender refuses the port, you are not stuck: a whole-of-market broker can test other lenders whose affordability models may treat your income more kindly. You would pay the ERC and lose the old rate, so weigh that cost against the move itself, or consider waiting until the fix ends. Porting is a useful right, but it is a right to apply, not a right to be approved.

Common questions

Do I have to pass affordability checks again to port my mortgage?

Yes. Porting is a full new mortgage application judged against the lender's current criteria, including affordability and credit checks and a valuation of the new property. Approval for the original loan, and a spotless payment record since, do not guarantee approval, which is why ports fail when income has fallen or outgoings have grown.

Can I port my mortgage and borrow more at the same time?

Usually, subject to affordability. The extra borrowing goes on a separate product at current rates, not on your ported rate, so you end up with two slices that may have different rates, fees and end dates.

Do I pay an early repayment charge if I port my mortgage?

Not on the amount you take with you, provided you complete within the lender's porting window. If you sell before you buy, you typically pay the ERC at redemption and it is refunded when the new mortgage completes in time (six months at HSBC, three at some lenders). Reduce the loan beyond your overpayment allowance and the ERC applies to the part left behind.

Can I port my mortgage if I am downsizing to a cheaper house?

Often yes, but if the new loan is smaller you can be charged the ERC on the portion you are not taking across, beyond your annual overpayment allowance. You still need to pass affordability checks on the smaller amount.

Is it better to port my mortgage or pay the ERC and remortgage?

It depends on the gap between your current rate and today's rates, the size of the ERC, and how long is left on your fix. If your rate is below the market, porting usually wins. If new rates are well below your fix, paying the ERC for one clean deal can come out ahead; run the break-even calculation with your own numbers.

Guidance and education, not regulated financial advice.