Moving Home: Porting Your Mortgage vs Getting a New Deal

When you sell one home and buy another, your existing mortgage has to go somewhere. You have two routes — take it with you (porting) or pay it off and start a new one — and the better option depends on your rate, your early repayment charge, and whether you need to borrow more.

Option 1: Port your existing mortgage

Most modern mortgages are "portable" — you repay the loan when you sell and immediately re-borrow the same amount on the same terms against the new property.

Worth knowing before you rely on it:

• Porting is not guaranteed. It is a new application — the lender re-checks affordability and values the new property. If your circumstances have changed, you can be declined.
• Borrowing more? The extra borrowing typically goes on a separate sub-account at whatever rate is currently offered — often different (and worse) than your ported rate, with its own deal end date.
• Borrowing less? You may pay an ERC on the portion you do not port.
• Timing matters. Ported mortgages usually require the sale and purchase to complete close together — the rules vary by lender, so ask early.

Porting makes most sense when your current rate is good (below what is on offer today) or your ERC is large.

Option 2: New mortgage, pay off the old one

Repay the existing mortgage from the sale proceeds — including any early repayment charge if you are still inside a fixed period — and take a fresh deal on the new property.

• If your ERC is, say, 2% of a £180,000 balance, that is £3,600 — enough to change the maths on whether switching is worth it.
• If you are outside your deal (on the SVR or in a penalty-free period), there is usually no ERC and switching is clean.
• A new deal means full affordability checks, valuation and legal work — factor in the time.

Stamp duty on the purchase

In England and Northern Ireland, standard residential rates (as at September 2026 — check gov.uk for current thresholds) are:

| Portion of price | Rate | |---|---| | Up to £125,000 | 0% | | £125,001–£250,000 | 2% | | £250,001–£925,000 | 5% | | £925,001–£1.5m | 10% | | Above £1.5m | 12% |

A £350,000 purchase currently costs £7,500 in SDLT. If you somehow end up owning two homes at completion (your sale fell through but you still bought), the additional-property surcharge — currently 5% on top of standard rates — applies, though you can reclaim it if you sell the original home within three years.

Scotland (LBTT) and Wales (LTT) have their own rates and no shared thresholds — check Revenue Scotland or the Welsh Revenue Authority.

The full cost of moving

On top of stamp duty, budget for:

• Estate agent fees — typically 1–1.5% + VAT for a high-street agent, less for online/fixed-fee agents
• Conveyancing — you pay twice: once to sell, once to buy, plus searches on the purchase
• Survey on the new property — do not skip it on an older home
• Mortgage costs — arrangement fee, valuation, broker fee if applicable
• Removals — from a few hundred pounds for a van-and-mates job to £1,500+ for a full packing service

A typical seller-and-buyer move in England easily runs £10,000–£20,000 all-in once stamp duty is included.

Chains and timing risk

Most moves sit in a chain — your buyer is waiting on their buyer, and so on. A few practical points:

• Nothing is binding until exchange. Either side can walk away until contracts exchange, which is why chains collapse. An agreement in principle and a responsive solicitor do more for your position than a slightly higher offer.
• A mortgage offer has an expiry date — usually 3–6 months. If your chain drags, check your offer will not lapse.
• Bridging loans exist for buying before you have sold, but they are expensive short-term borrowing — treat them as a last resort, not a planning tool.

If you are moving because money is tight

If the move is driven by affordability, speak to your lender before you miss a payment — they have formal forbearance options (term extensions, temporary interest-only, payment holidays in some cases) that work better before arrears start. MoneyHelper covers all of them.

This guide is general information, not mortgage or financial advice. Tax thresholds and mortgage rules change — verify current figures before you budget.