Answers · UK 2025/26
How does mortgage porting work when moving house?
Porting lets you transfer your existing mortgage deal — including its current interest rate — onto a new property when you move, avoiding early repayment charges you would otherwise pay for exiting the deal early. You still need to reapply and pass the lender's affordability and property checks as if it were a new application, and any additional borrowing needed is usually arranged as a separate, new-rate loan alongside the ported amount.
Full answer
Mortgage porting allows a borrower who is part-way through a fixed, tracker or discounted-rate deal to move house without paying the early repayment charge (ERC) that would normally apply for ending the deal before its agreed term — the existing rate and remaining term are effectively transferred across to the new property instead. Crucially, porting is not automatic just because your mortgage product is described as "portable" (most residential mortgages are) — you still need to formally reapply with the lender for the new property, going through a fresh affordability assessment based on your current income, outgoings and credit record, as well as a valuation and legal checks on the new property, exactly as you would for a brand new mortgage application. This means porting can still be refused, or offered on different terms, if your circumstances have changed significantly since the original mortgage was arranged (for example, reduced income, new debts, or a lower credit score), even though the underlying rate you are hoping to keep has not changed. If you need to borrow more to afford the new property (a common scenario when moving to a larger or more expensive home), the additional amount is typically arranged as a separate new sub-account at the lender's current rates for a similar term, sitting alongside the ported original balance and rate rather than blending into a single rate — so your overall mortgage becomes a combination of the old ported rate on the original balance and a new rate on the extra borrowing. If you are moving to a cheaper property and porting less than your current outstanding balance, most lenders will charge an ERC on the portion of the loan you are not porting across, since that portion is effectively being repaid early. Timing also matters: most lenders require the sale of the old property and purchase of the new one to complete on the same day, or within a short window either side, for porting to apply cleanly. Use the Mortgage calculator to compare porting against remortgaging onto a new deal entirely.
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This answer is informational only and does not constitute financial, tax or legal advice. Figures are for the 2025/26 UK tax year. See our methodology and sources.