Can I Port My Mortgage to a New House UK?

Yes — most UK fixed-rate mortgages are portable, meaning you can move them to a new property without paying the Early Repayment Charge (ERC) for breaking the fix. You keep your existing interest rate, but the lender re-runs affordability checks and the new property must meet their valuation and criteria. If you’re buying a more expensive home and need additional borrowing, a top-up loan at current market rates is added. The ERC applies only if you actually leave the lender entirely.

This is how mortgage porting works in 2026/27.

What “porting” actually means

When you move home, your mortgage either:

• Stays with you (gets ported to the new property), or
• Gets paid off with the sale proceeds, and you take a new mortgage on the new property.

Porting keeps your existing mortgage product — same lender, same rate, same fix expiry — but moves the lien from your old house to your new house.

The process:

1. Sell your existing home.
2. Buy a new home.
3. Lender redeems the old mortgage and creates a new mortgage on the new property, with the same terms.

The lender doesn’t literally “move” the mortgage — the old loan is paid off and a new one is created. But for product, rate and ERC purposes, they treat it as a continuation.

Why porting matters

The main reason: avoiding the Early Repayment Charge (ERC).

Most fixed-rate mortgages have ERCs of 1–5% of the outstanding balance if you pay off early. For a £250,000 mortgage with a 3% ERC, that’s £7,500 — a real cost if you can’t port.

Porting also lets you keep:

• A favorable rate that’s no longer available.
• The remaining fix term length without re-applying.
• Your overall mortgage structure.

For someone who fixed at 2.0% in 2020/21 (when rates were unusually low), being able to port to a new home means keeping the historic rate rather than remortgaging onto today’s much higher rates.

What lenders check when you port

Porting isn’t automatic. The lender treats it like a fresh application in several ways:

1. Affordability re-check

Your current income, expenses and debts are reassessed. Even though you’ve been paying the mortgage successfully, the lender wants to confirm you can afford payments on the new property.

If your circumstances have deteriorated (lost a job, taken on debts, gone self-employed), the lender may not approve the port — or may approve at a reduced borrowing level.

2. Property valuation

The new property must meet the lender’s valuation and acceptability criteria:

• Not on a cladding-affected building (post-Grenfell criteria).
• Standard construction (not pre-fabricated, ex-public-housing-non-traditional, etc.).
• Acceptable EPC rating in some cases.
• Sensible LTV based on new property value.

If the new property is below the lender’s standards, they decline the port.

3. New LTV calculation

The lender calculates LTV based on the new property value and the outstanding mortgage:

• If selling at £300,000 with £180,000 mortgage outstanding (60% LTV), and buying at £400,000 with £240,000 needed... the new LTV is 60% — same as before.
• If the new LTV is higher (you’re moving up to a more expensive home), the lender may apply different rates to the additional borrowing.

What if I need to borrow more?

Often the case when upsizing. You sell £300k, buy £400k, need £100k extra mortgage.

The lender typically:

• Ports the existing mortgage at the existing rate.
• Adds a top-up loan at current market rates for the additional borrowing.

So if your existing mortgage is at 2.5% (fixed pre-2022) and current market rate is 4.5%:

• Port £180,000 at 2.5%.
• Additional £100,000 at 4.5%.
• Blended effective rate: ~3.2%.

This is materially better than fully remortgaging the whole loan at today’s rates.

What if I’m downsizing or paying off some mortgage?

If you’re moving to a less expensive home or paying down the mortgage:

• The ported mortgage is for a smaller amount.
• Some lenders apply the ERC on the amount paid off rather than letting you reduce the mortgage without penalty.

For example, if you have a £250,000 mortgage and want to port only £200,000 to the new property (paying off £50,000):

• The £50,000 you’re effectively paying off may trigger an ERC (typically the same % as full early redemption).
• £50,000 × 3% ERC = £1,500.

Some lenders allow this within the standard 10% overpayment allowance. Check your terms.

Timing issues with porting

Porting requires the sale and purchase to complete simultaneously (or within a short window — typically 90 days).

If you sell first and don’t buy immediately:

• Mortgage is redeemed.
• ERC may apply.
• You become a non-borrower, then have to start fresh when buying.
• New mortgage at current rates.

This is one of the biggest porting traps — if your buyer’s chain falls through or your purchase is delayed, you can lose the port.

The fix: bridge financing or staying in temporary accommodation while the new purchase progresses. Both are expensive but cheaper than ERC + remortgage premium.

When porting isn’t possible

Several scenarios where porting doesn’t work:

• Lender changed criteria: the new property doesn’t meet their current standards.
• Your affordability deteriorated: lender can’t justify the port.
• The product is no longer available: legacy products may not be portable to new properties.
• Specific product terms: a small number of mortgage products are explicitly non-portable. Check your offer document.
• Timing: sale and purchase don’t complete close enough together.

In any of these cases, you remortgage onto a new product — paying ERC if applicable on the old one.

Worked example: porting during a move

Tom has a £180,000 fixed-rate mortgage at 3.5%, with 3 years remaining on a 5-year fix. He sells his £300k home and buys a £380k home.

His position:

• Net sale proceeds: £300,000 − £180,000 (mortgage outstanding) − selling costs (~£8,000) = £112,000.
• He puts £112,000 toward the £380,000 purchase as deposit.
• Needs £268,000 mortgage on new property.

Porting plan:

• Port £180,000 at 3.5% (his existing rate).
• Top up £88,000 at current market rate of 4.7%.
• Blended rate: ~3.9% on combined £268,000.

Without porting:

• ERC on £180,000 at 3% = £5,400.
• Full mortgage at current 4.7% rate.
• Cost saving over 3 remaining years of his fix: significant on the £180k portion.

Total savings from porting: ~£8,000–£12,000 over the remaining fix period, vs paying ERC and remortgaging at full current rates.

Internal links

• How does remortgaging work and when should I do it?
• Can I overpay my mortgage to clear it early?
• What fees do I pay when buying a house UK?

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This guide is information, not regulated financial advice. UK mortgages are regulated by the FCA — speak to a regulated mortgage adviser before relying on the porting option in a specific move.