How porting your mortgage works and where it fails

Porting means taking your existing mortgage deal to a new property, so you keep the rate instead of paying an early repayment charge to leave it. The loan itself does not move. Nationwide describes it as paying off an existing mortgage and taking out a new one on the same terms on a new property, which is a transfer of the mortgage deal rather than the loan. You have to reapply and meet the lender’s current lending criteria.

Only the existing balance keeps the rate

When you port, the rate stays on the amount you already owe. Anything extra you need to borrow is on a new deal at current terms, which Nationwide, Lloyds and Principality all say in their own porting rules.

Moving up usually means borrowing more, so most ports end up as two products on one property with two rates. Check when each part ends before you accept the extra borrowing. If the two parts expire on different dates, the second may still carry an early repayment charge when the first ends, and that limits your options at the first expiry. Ask whether the lender can line the end dates up at the application stage.

Where ports fail

The failure points are predictable, and you can test all of them before you offer on anything.

Affordability is checked again. Lloyds says you will need to pass its affordability checks again, and Which? says that if your circumstances have changed, you might not qualify. A change in income, a new credit commitment or a bigger loan can all lead to a decline, or to a different loan amount, even if you are paying your current mortgage without difficulty.

The new property has to meet the lender’s criteria too. Nationwide lists the loan to value of the new property among the reasons a port may not be possible, and Lloyds needs a valuation of it. Flats above commercial premises, short leases and non-standard construction can cause problems that had nothing to do with your old house. Our guide to non-standard construction covers one of the common ones.

Timing is the third. Porting assumes the sale and the purchase complete together.

The early repayment charge and the completion gap

Nationwide says there is no early repayment charge if you take all of your existing mortgage to a new property and complete the sale and the purchase on the same day. If there is a gap between the two, the charge may apply, but it is refunded in full if you port to the new property within 180 days of the sale. Leave it longer than 180 days after paying off the old mortgage and the old deal and its rate are lost, so you apply again at current rates.

Porting only part of the mortgage costs money even when everything else goes right. If you borrow less on the new property than you owe now, the difference is repaid on completion and the charge applies to that amount. As an illustration, take a £200,000 balance with a 3% early repayment charge. Leaving entirely costs £6,000. Downsizing and porting £150,000 of it leaves £50,000 repaid early, and 3% of that is £1,500. Nationwide says there is no early repayment charge on additional borrowing.

These windows are lender-specific. Nationwide gives 180 days and Principality gives six months from repaying the old account to completing on the new property. Lloyds gives no figure and says a refund is not guaranteed. Do not plan a sale, rent, then buy sequence on a number you have read about another lender. Our guide to selling a house with a mortgage covers how porting fits into a sale.

What to do before you accept an offer

Ask your lender two questions in writing and keep the answers. First, how long you have to complete the purchase after the sale completes, and whether the early repayment charge is refunded or only waived. Second, what the port would look like with the extra borrowing you expect to need, including both rates and both end dates.

Get those answers before you accept an offer on your house, because once a chain is forming you can lose the chance to choose a completion date that suits your mortgage. If porting does not work, compare the early repayment charge with the saving from a new deal elsewhere. That is worth working out on paper rather than assuming the charge decides it. Ask for quotes for the legal work on your move at the same time, since a same-day sale and purchase needs a conveyancer who can hold both ends to one date. Our guide to how to choose a conveyancer covers what to compare.