Porting Your Mortgage When Moving House in the UK

Key Takeaway

Porting your mortgage lets you transfer your existing deal to a new property and avoid early repayment charges, but you are locked into your current rate even if better deals exist. Remortgaging gives you access to the whole market and potentially lower rates, but you may face early repayment charges of 1% to 5% of the outstanding balance if you are still within your deal period. The right choice depends on how your current rate compares to the market, the size of any exit fees, and whether your new property value requires borrowing more or less.

What Porting a Mortgage Means

Porting is the process of transferring your existing mortgage deal from one property to another when you move house. Most fixed-rate, tracker, and discount mortgages in the UK offer portability as a feature, allowing you to keep your current interest rate, remaining deal period, and terms when you sell and buy at the same time. According to MoneyHelper, porting avoids early repayment charges (ERCs) that would otherwise apply if you exit your deal early, which can range from 1% to 5% of the outstanding loan.

The alternative is to remortgage: repay your current loan (paying any applicable ERCs), then arrange a new mortgage on the new property at current market rates. As covered in foundational finance texts such as Principles of Finance, the choice between keeping an existing fixed-rate commitment and refinancing hinges on comparing the locked-in cost against prevailing market conditions and the transaction costs of switching.

Port vs. Remortgage: Summary Comparison

Factor	Porting Your Mortgage	Remortgaging
Interest rate	Keep your existing rate	Access current market rates
Early repayment charge	Avoided (if completed within the lender’s window)	May apply if within deal period (1% to 5%)
Product choice	Locked to your current deal	Full market access
Flexibility	Must move within lender timescales (often 3 to 6 months)	No strict completion deadline
Borrowing more	Often requires a second sub-account at a different rate	Single new mortgage at one rate
Lender approval	Not automatic; subject to fresh affordability and valuation	Subject to affordability and valuation across all lenders
Fees	May incur valuation and legal fees; no product fee if porting same deal	Arrangement fee, valuation, legal costs, possible ERC

When Porting Makes Sense

Your current rate is better than the market. If you locked in a 1.5% five-year fix in 2021 and market rates in 2026 sit at 4.5%, porting preserves a significant saving for the remaining deal period. The ERC you avoid (for example, 3% of £200,000 equals £6,000) plus the interest-rate difference can outweigh any porting fees.

You are early in a fixed or discounted deal. ERCs are typically highest in the first year or two and taper off. Porting in year one of a five-year fix avoids the steepest penalties.

The new property value is similar. If you are moving from a £250,000 home to a £260,000 home and your outstanding mortgage is £200,000, you can port the full £200,000 and add a small cash deposit, keeping the process straightforward.

Your lender offers portable products and approves the new property. Not all lenders permit porting, and approval is not automatic. The lender reassesses your affordability and the new property’s valuation; if either fails, porting is refused and you revert to remortgaging or finding a new lender.

When Remortgaging Is Better

Market rates have fallen below your current deal. If you are paying 4.5% and new two-year fixes are available at 3.5%, the lower rate over the life of the new mortgage may cover the ERC and still save money. Calculate the break-even point: ERC divided by monthly saving tells you how many months until you recover the fee.

You need to borrow significantly more or less. If your new property requires an extra £100,000, your lender may offer the additional borrowing as a separate sub-account at a higher rate, leaving you with two interest rates on one mortgage. A single new mortgage at one competitive rate is often simpler and cheaper. Conversely, if you are downsizing and borrowing much less, a new lower LTV mortgage may unlock better rates than porting your old higher-LTV deal.

Your current lender’s porting terms are restrictive. Some lenders require you to complete the sale and purchase simultaneously or within a tight window (often 90 days). If your chain is uncertain or you plan to rent between moves, porting becomes impractical. Remortgaging gives you control over timing.

You want access to cashback, incentives, or free legals. New mortgage deals in 2026 often include free valuation, free legal work, or cashback offers. Porting keeps your existing product, which may carry higher arrangement fees and no incentives.

Practical Scenarios and Recommendations

Young family upsizing mid-fix. You are two years into a five-year fix at 1.8%, moving from a £200,000 flat to a £350,000 house, borrowing an extra £80,000. Port the £180,000 outstanding balance to keep the 1.8% rate and take the £80,000 top-up at your lender’s current rate (say 4.2%). You avoid a 3% ERC (£5,400) and benefit from the low rate on the majority of the loan. Trade-off: managing two sub-accounts and a blended rate.

First-time mover near end of deal. You are in the final year of a two-year fix at 3.9%, moving from a £180,000 starter home to a £220,000 property. The ERC is now 1%, and new rates are 3.6%. Remortgage: pay the £1,800 ERC, access the better rate, and shop the whole market for incentives. The lower rate quickly recoups the penalty.

Downsizer post-retirement. You are selling a £400,000 family home and buying a £250,000 bungalow, reducing your mortgage from £150,000 to £80,000. Remortgage at a lower LTV (32% instead of 37.5%), unlocking better pricing tiers. Porting offers no advantage when your borrowing and risk profile improve substantially.

Rate-locked professional moving for work. You are one year into a five-year fix at 2.1% (market rates now 5.0%), relocating for a job, moving from a £300,000 to a £310,000 property. Port the mortgage: the 4% ERC (£9,600 on £240,000 outstanding) far exceeds any benefit from remortgaging, and the rate saving over four remaining years is significant.

Common Questions

Can I port if I am moving to a cheaper property?
Yes, but you will repay the difference and your lender will reassess affordability on the lower loan. Some products allow partial porting without ERC on the amount you keep.

What happens if my porting application is declined?
You must either remortgage with a new lender or pay the ERC to your current lender and find alternative financing. Porting is not guaranteed.

How long do I have to complete the port?
Lender policies vary; typically 3 to 6 months from the sale of your old property to completion on the new one. Check your mortgage terms and confirm the window with your lender early in the moving process.

Do I pay arrangement fees again when porting?
Usually no product fee applies if you are porting the same deal, but you will incur valuation and legal costs on the new property. If you borrow additional funds, that portion may attract a new arrangement fee.

Conclusion

Porting your mortgage preserves your current rate and avoids early repayment charges, making it the right move when your deal is better than the market or ERCs are high. Remortgaging opens the whole market, suits those whose circumstances have changed, and works best when rates have fallen or you need significantly different borrowing. Compare your current rate against market offers, calculate any ERCs and fees, and consider your timeline and flexibility needs. According to the Financial Conduct Authority, mortgage advice must be tailored to your situation; speak to an FCA-authorised mortgage adviser to confirm which route saves you money and fits your move.

Financial Disclaimer: This article provides general educational information about mortgage porting and remortgaging in the UK. It is not regulated mortgage advice, and it is not personalised financial, lending, or legal advice. Refisage is not authorised by the Financial Conduct Authority (FCA). Your home may be repossessed if you do not keep up repayments on your mortgage. Product availability, interest rates, early repayment charges, porting terms, and fees vary by lender and your personal circumstances; rates and deals change frequently. Always confirm current terms with an FCA-authorised mortgage adviser before making any decision. For tailored guidance on porting versus remortgaging in your situation, consult an FCA-authorised mortgage adviser or contact MoneyHelper for free, impartial support.