Quick summary For more information, see FCA regulated mortgage advice.
- You can often port (transfer) your existing mortgage deal to your new property to avoid early repayment charges
- Porting is not automatic: your lender will reassess your affordability and the new property
- If you need to borrow more, the additional amount will usually be at a separate, new rate
- Always compare porting against taking a fresh deal before deciding
Moving home is one of the most significant financial decisions most people make, and yet the mortgage side of it often gets less attention than the property search itself. Whether you have years left on a fixed rate, want to upsize significantly, or are simply trying to understand your options before committing to anything, getting the mortgage right can save you thousands of pounds and a great deal of stress.
This guide covers the full picture: what porting means and how it actually works, when it makes sense and when it does not, what costs to expect, and how to approach the whole process in a way that gives you the most choice.
What is porting a mortgage?
Porting means transferring your existing mortgage deal, including its interest rate, to your new property. The appeal is straightforward: if you fixed your rate at 2% and the market has since moved to 5%, carrying that 2% deal across to your new home saves you a significant sum each month.
However, porting is not as simple as updating your address. Legally, your current mortgage is discharged when you sell your home and a new mortgage is created on the new property. Your lender applies the same rate and terms as before, but you will go through a full application process including a new property valuation and a fresh affordability assessment.
Important to understand
Just because your mortgage is described as portable does not mean the port will automatically be approved. Your lender will reassess your income, outgoings and credit history at the time of the application. If your circumstances have changed since you originally took out the mortgage, approval is not guaranteed.
The porting process step by step
Check whether your mortgage is portable
Most mainstream mortgages are portable, but not all. Check your original mortgage offer document or call your lender. The portability clause will tell you whether the option exists and any conditions attached to it.
Understand your porting window
Most lenders give you a window to complete the new purchase after your existing mortgage is discharged. Nationwide offers up to 180 days. Halifax is broadly similar. Some lenders offer as little as 30 days. If your chain breaks or falls through, this window can expire and you may lose the port entirely.
Apply with your current lender
Submit a new application to port the mortgage. Your lender will carry out a fresh affordability assessment, a credit check and a valuation of the new property.
Handle any additional borrowing
If your new property costs more than your existing mortgage balance, you will need to borrow more. The additional amount is typically offered at a current rate, separate from your ported deal. You end up with two mortgage parts at two different rates.
Complete both sales simultaneously
Your solicitor coordinates the sale of your current home and the purchase of your new one. Timing is critical: delays in the chain can affect your porting window.
Porting vs taking a fresh deal
Porting is not always the best financial decision, even if it seems obvious on the surface. Before you commit, compare the total cost of porting against taking a new mortgage deal entirely.
| Factor | Porting | New deal |
|---|---|---|
| Your existing rate | Kept for the ported balance | Lost; new rate applies to full balance |
| Early repayment charges | Avoided on ported amount | May apply if mid-fix |
| Additional borrowing rate | Separate new rate, often higher | Single rate for whole balance, may be lower overall |
| Flexibility | Constrained by your lender’s criteria | Full market available |
| Legal costs | Lower (staying with same lender) | Full legal and valuation fees |
Example: when porting can actually cost more
A borrower has £200,000 remaining on a 2.5% fix with two years left and is buying a £350,000 home. She ports the £200,000 at 2.5% and borrows an additional £50,000 at the current rate of 5.2%. The blended rate on £250,000 is around 3.0%. But a new 5-year fix at 4.2% on the full £250,000 might be cheaper overall once you factor in the arrangement fee savings and the fact that the two-part structure ends at different times, creating future complexity. A broker can model both scenarios in full.
The costs of moving home
Beyond your mortgage payments, moving home comes with a range of costs that are easy to underestimate. Planning for these in advance avoids financial pressure at exactly the wrong moment.
| Cost | Typical range | Notes |
|---|---|---|
| Stamp Duty Land Tax | Varies by price and circumstance | Payable even when porting; use our calculator for a precise figure |
| Early repayment charge | 1% to 5% of remaining balance | Only if breaking your fix early (porting avoids this) |
| Mortgage arrangement fee | £0 to £2,000 | For any new product or top-up borrowing |
| Solicitor and conveyancing | £1,500 to £3,500 | Required for both the sale and purchase |
| Survey | £500 to £1,500 | Strongly recommended on any property purchase |
| Removal costs | £800 to £3,000 | Varies significantly by distance and volume |
When a port gets refused
If your lender refuses the port, you have two main options. You can break the existing deal, pay any early repayment charges and take a new mortgage entirely. Or you can carry out a product transfer with your existing lender, swapping to a new product from their current range without fully breaking the deal.
Neither option is automatically better. The right answer depends on your remaining deal period, the size of the early repayment charge, your current income and credit position, and what rates are available in the wider market. A broker can model all of these scenarios and give you a clear comparison.
Upsizing versus downsizing
The experience of moving looks quite different depending on whether you are upsizing or downsizing.
Upsizing: You will almost certainly need to borrow more. The additional borrowing sits alongside the ported amount at a new rate. Affordability is assessed on the full new mortgage amount, so changes in your income or outgoings since you last applied matter. If your situation has improved significantly, you may actually get a better deal by going to the open market rather than sticking with your existing lender.
Downsizing: If you are moving to a cheaper property, you may be able to port the mortgage and repay the difference from the sale proceeds. Some lenders allow partial repayment without charges when porting; others do not. Check your mortgage terms carefully, as early repayment charges could apply to any lump sum you pay down.
Frequently asked questions
Can I port my mortgage to a property abroad?
No. UK lenders will only port a mortgage to a property in the UK. For overseas property, a separate mortgage product is required.
What happens if my port application is declined?
You will need to either pay early repayment charges to break the existing deal, arrange a product transfer with your current lender, or wait until the fixed rate period ends before moving. A broker can help you work out which approach costs less in your specific situation.
Do I need a solicitor when porting?
Yes. Even though you are staying with the same lender, you are buying a new property. Conveyancing is required for the purchase, and your solicitor will also handle the discharge of the existing mortgage on your sold home.
Can I extend my mortgage term when porting?
Usually yes, subject to your lender’s criteria and age limits. Extending the term reduces monthly payments but increases total interest paid. It is worth modelling both scenarios rather than automatically taking the longer term.
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