If you're moving house partway through a fixed-rate deal, the thought of paying an Early Repayment Charge just to move can feel like an unfair penalty for simply relocating. "Porting" your mortgage is designed to solve exactly this problem — but it comes with more conditions than many homeowners expect.
What porting actually means
Porting allows you to transfer your existing mortgage deal — including its interest rate and remaining term — from your current property to a new one, avoiding the Early Repayment Charge you'd otherwise pay for ending the deal early. Most (though not all) UK mortgages are portable, but porting isn't automatic or guaranteed; it's better understood as an option your lender may allow, subject to a fresh assessment.
Why porting isn't as simple as "taking your rate with you"
What happens if you need to borrow more or less
If your new home costs more than your current one, you'll typically need additional borrowing on top of the ported amount — and that extra portion is usually taken out at current rates, not your original rate, meaning you could end up with a blended rate across two portions of the same mortgage. If you need to borrow less, the ported amount is simply reduced, sometimes triggering a partial Early Repayment Charge on the amount you're not carrying forward, depending on your lender's specific terms.
Step-by-step: how porting typically works
- Check your mortgage terms to confirm porting is available and understand any conditions attached.
- Get a mortgage in principle from your existing lender for the new property and any additional borrowing needed.
- Sell your current property and agree a purchase on the new one, ideally with completion dates that align closely.
- Submit a full application — your lender reassesses affordability and instructs a valuation on the new property.
- Complete both transactions, ideally simultaneously, so your existing mortgage is redeemed and the ported (plus any new) mortgage begins on the new property.
Why timing alignment matters so much
Porting generally requires your sale and purchase to complete on the same day, or very close together — a genuine challenge in a property chain. If timings don't align, you may need a bridging solution or, in some cases, lose the ability to port and face an Early Repayment Charge after all, so discussing this risk with your lender or broker early is worthwhile.
When porting makes sense
- Your current rate is meaningfully better than what's available on the open market today
- You're well within your fixed term, where the Early Repayment Charge would otherwise be substantial
- Your income, circumstances and the new property are all likely to pass a fresh affordability and valuation check
When it might not be worth pursuing
If market rates have fallen since you took out your original deal, or your circumstances have changed such that a fresh application elsewhere might get you a better outcome anyway, porting may not actually be the cheapest option — it's always worth comparing the ported rate (plus any blended additional borrowing rate) against what a full remortgage to a new lender might offer.
You may also find our guides on Early Repayment Charges When Remortgaging Explained and How to Switch Mortgage Lenders for a Lower Rate useful.
Our free Mortgage Affordability Calculator can help you check this against your own figures.
The bottom line
Porting can be a genuinely valuable way to avoid an Early Repayment Charge when moving home mid-deal, but it still involves a full reassessment, careful timing between your sale and purchase, and isn't automatically the cheapest route. Speak to your lender or a broker early in your moving process to understand exactly what porting would mean for your specific numbers.