When you move, you face a key choice: take your existing mortgage with you by porting, or switch to a new mortgage. Which is cheaper depends on your deal and the market. This guide explains porting versus a new mortgage, helping you weigh the costs and choose the better option.
The two options
When moving, you can either port your existing deal to the new home, keeping its rate and terms, or repay your current mortgage and take out a new one, as our guide to porting explains. Porting keeps your rate and avoids an early repayment charge, while a new mortgage opens up the whole market. Which is cheaper depends on comparing the two for your particular situation.
When porting wins
Porting tends to win when you have a competitive rate worth keeping and would otherwise face an early repayment charge for leaving your deal. If your current rate is lower than today's deals, porting lets you keep it, and you avoid the charge, as our guide to ERCs explains. In this situation, porting can be clearly cheaper than taking a new mortgage at higher current rates.
When a new mortgage wins
A new mortgage tends to win when today's rates are lower than your current deal, or your existing deal is not worth keeping. Even if leaving triggers an early repayment charge, a much better new rate can outweigh it over time. A new mortgage also opens up the whole market and lets you change your borrowing, so where current deals are attractive, switching can be the cheaper and more flexible choice.
Doing the maths
To decide, compare the total cost of each option. For porting, consider your current rate and any fees. For a new mortgage, consider the new rate, any early repayment charge for leaving your current deal, and any fees. Work out which leaves you better off over a sensible period. Often the difference comes down to whether your current rate beats today's deals by enough to outweigh the early repayment charge.
The top-up rate issue
If you are borrowing more, porting usually means keeping your existing rate on the original balance and taking the extra as a top-up at a current rate, as our guide to borrowing more when you move explains. This can leave you with two parts on different rates and end dates. A single new mortgage avoids this split, which is simpler, so the convenience of one deal is part of the comparison.
Flexibility and the whole market
A new mortgage gives you access to the whole market and the freedom to change your term, lender or borrowing, while porting ties you to your existing lender and deal. If you want flexibility or a fresh start, a new mortgage offers it, whereas porting is about preserving a good existing deal. Weighing how much you value flexibility against keeping your current rate is part of choosing between them.
Getting advice
Because the comparison depends on rates, charges and your circumstances, advice can be valuable. A mortgage broker can calculate the total cost of porting versus a new mortgage for your move and recommend the cheaper option. Given the sums involved, getting this right can save a worthwhile amount, so it is often worth having the comparison done properly rather than guessing which route is better.
A worked comparison
Imagine your current deal is at a low rate with two years left and a 3% early repayment charge on a £180,000 balance, which is £5,400. If today's rates are higher than your deal, porting keeps your low rate and avoids that £5,400, so porting likely wins. If today's rates are much lower than your deal, a new mortgage might save more than £5,400 over time, so switching could win. The numbers decide.
Do not forget the fees
Both options can carry fees. Porting may involve a valuation and a fee on any additional borrowing, while a new mortgage may have an arrangement fee, valuation and legal costs, though these are often free on remortgage-style deals, as our guide to mortgage costs explains. Including all the fees on each side, not just the headline rate, gives a fair comparison of which option is genuinely cheaper.
Your circumstances matter
Your circumstances affect the choice too. If your income or credit has changed since you first borrowed, porting, which still requires passing the lender's checks, or a new application, might be harder, which can tip the decision. The new property must also qualify. So the better option depends not just on rates and charges but on whether you can readily obtain each, which is worth considering early in your planning.
The convenience factor
Porting keeps you with your current lender and deal, which can be simpler, while a new mortgage means a full application and possibly a new lender. For some, the simplicity of porting has value, while others prefer the fresh choice a new mortgage brings. Convenience is a legitimate part of the decision alongside cost, though for a large mortgage the potential savings usually matter more than the modest difference in effort.
If rates have risen since you fixed
If you fixed when rates were lower and they have since risen, your current deal may be better than anything available now, making porting especially valuable, since it preserves that advantageous rate. In this common situation, porting can save a great deal compared with taking a new mortgage at today's higher rates. Recognising when your existing deal is worth protecting is key to deciding in favour of porting.
Let a broker run the numbers
Because the comparison depends on your rate, the early repayment charge, current deals, fees and your circumstances, it is an ideal task for a mortgage broker, who can run the numbers for both options and recommend the cheaper one. Given that the difference can amount to thousands of pounds on a sizeable mortgage, having the comparison done properly is usually well worth it.
Ultimately, neither porting nor a new mortgage is always best; the right choice is simply whichever leaves you better off once every cost is counted. Comparing them carefully for your move, rather than assuming, ensures you finance your next home in the most cost-effective way.
It helps to start this comparison early, before you have even found a home, so you have a clear idea of your likely route and any early repayment charge. Going into your move knowing roughly whether porting or a new mortgage suits you lets you act decisively, and you can confirm the precise figures once you have a specific property and purchase price in view.
In short
Porting versus a new mortgage comes down to cost. Porting wins when you have a good rate worth keeping and would otherwise pay an early repayment charge. A new mortgage wins when today's rates are lower, even after any charge, and offers more flexibility. Do the maths on the total cost of each, factor in the top-up rate when borrowing more, and consider advice to choose the cheaper option.
Where to get help and next steps
Read our guides to porting a mortgage, moving during a fixed-rate deal, and borrowing more when you move. This is general information, not mortgage or financial advice.