Porting
Last checked UK · illustrative onlyNot a lender or brokerAboutDisclaimer
Published by Rodway Labs — not a mortgage adviser
Published · Last revised
Porting: Taking an existing mortgage deal to a new property, if the lender agrees, instead of redeeming it and starting again.
Porting is not automatic. The lender reassesses you and the new property, usually including affordability and a valuation, and can decline. Whether a deal is portable, and on what terms, is set out in your offer.
If you port and borrow more, UK lenders usually put the extra borrowing on a separate product with its own rate, fees and ERC. The new home also has to pass the lender’s valuation and criteria, so porting is applied for, not automatic.
Example: moving home with 4 months left on the deal
- Existing deal
- £185,000 at 4.19%, 4 months left, ERC 2%
- Full redemption instead of porting
- ERC 2% × £185,000 = £3,700
- Smaller new loan of £160,000
- £25,000 repaid · ERC 2% on that part = £500, if the offer charges on the repaid amount
- Larger new loan of £210,000
- £185,000 ported · the extra £25,000 is new borrowing on the lender’s terms
Illustrative only, using the site ERC estimator for the repaid part. Whether the charge applies to the repaid amount, the whole balance or neither depends on the offer wording.
How it affects a remortgage
Porting is mainly a way to avoid an early repayment charge when you move during a deal. In the example, redeeming in full would cost £3,700, far more than any likely rate difference.
Ask early. Porting needs a fresh application, which has to run alongside the purchase timetable.
With only a few months left, it can be worth checking whether completion could fall after the ERC ends. Porting then matters less, and the whole market is open again.
Extra borrowing on a port is usually a separate product with its own rate, fee and charge, so you can end up with two deals on one home. This site does not model porting. Use the ERC estimator for any part you might repay, and the lender’s illustration for the rest.
Example: two deals after porting and borrowing more
- Ported part
- £185,000 at 4.19% · about £1,073.81 a month · 4 months left on that deal
- Extra borrowing
- £25,000 at an example 5.97% over 22 years · about £170.33 a month
- Combined payment
- about £1,244.13 a month
- Renewal dates
- two: one in 4 months for the ported part, one when the new part’s deal ends
Illustrative only. 5.97% is the site example rate, used to show the structure, not a price for additional borrowing. The lender sets the rate, fee and ERC on any new part.
Common mistakes
- Assuming porting is guaranteed. MoneyHelper notes most mortgages are portable but you still have to pass the lender’s affordability checks, and the new property has to suit the lender.
- Expecting the whole loan to move on the old deal. Usually only the existing balance keeps the current rate; extra borrowing goes on a new deal with different terms.
- Starting late. Porting is a fresh application, run alongside a purchase.
- Forgetting the split end dates, which mean two decisions later.
- Forgetting the purchase timeline. The FCA notes a mortgage offer normally stands for 3 to 6 months, so a long chain can mean checking whether the offer will still be valid at completion.
Edge cases
- Failing the checks. MoneyHelper notes that if you do not pass the lender’s affordability checks on a port, the only option may be another lender, which means paying the existing ERC.
- Borrowing less. Any part repaid may carry an ERC; the example £25,000 repaid at 2% is £500.
- Deal close to its end. With four months left, timing completion after the ERC ends can remove the need to port.
- Putting everything on one new deal. MoneyHelper mentions this as an alternative to two deals; which works out cheaper depends on the ERC, the fees and the rates.
Where to go next
- ERC estimator — the charge on a full or part repayment.
- How ERCs are calculated — percentage and months-of-interest methods.
- The remortgage process — what happens if you redeem and start again.
Sources checked 2 November 2026
- MoneyHelper: remortgaging to cut costs — remortgage and product transfer definitions, switching costs, LTV formula, valuations, porting and negative equity.
- FCA: support with mortgages and interest rates — offers typically valid 3 to 6 months, reversion rates, same-lender switches, ERCs and stress testing.
Figures marked example are illustrative only, not a quote and not lender, broker or FCA-regulated advice. Definitions are plain English for this site, not the wording in your offer. The definitions and explanations are in our own words. Last checked 2 November 2026.