The short answer
Moving to a bigger house involves stamp duty, estate agent fees, legal costs and removal costs that can easily total £20,000–£60,000 or more, depending on property values — often comparable to or exceeding the cost of a well-designed extension. However, extending has limits; some needs can only be met by moving. See extension costs and whether an extension adds value.
For families who have outgrown their home, the choice between extending and moving is often framed as a lifestyle decision. But it is equally a financial one, and the numbers are not always as obvious as they first appear. The true cost of moving — once stamp duty, agent fees, conveyancing and removal are included — can be surprisingly large. The true cost of extending — once design, fees, contingency and disruption are included — can also be more than the headline build cost. This guide gives you the framework to compare both options honestly.
Extension vs moving: the key numbers
- Moving costs (typical) Stamp duty + agent + legal + removal = £20k–60k+
- Extension costs (typical) £25,000–£90,000 depending on type and spec
- Stamp duty (at £400k) £10,000 (standard rates, 2026 — check current rates)
- Estate agent fee 1–3% of sale price, plus VAT
- Extension advantage No stamp duty, no chain, you choose the design
- Moving advantage New location; more space than extension can deliver
The real cost of moving
The sticker price of a bigger house is only part of the cost of moving. On top of the purchase price, moving involves:
- Stamp Duty Land Tax (SDLT): on a property purchased for £400,000 in 2026, SDLT is approximately £10,000 at standard residential rates. The rate increases progressively above £250,000. Check the current rates on GOV.UK, as they change.
- Estate agent fee: 1–3% of the sale price of your current property, plus VAT. On a £300,000 sale, that is £3,000–£9,000.
- Conveyancing: legal fees for selling and buying, typically £2,000–£4,000 combined, including searches and disbursements.
- Surveyor: a HomeBuyer Report or Building Survey on the new property, £500–£1,500.
- Removal: £1,000–£4,000 for a professional removal company, depending on volume and distance.
- Immediate works on the new property: most buyers decorate, update kitchens or bathrooms — typically £5,000–£20,000 or more.
| Moving cost item | Typical range |
|---|---|
| Stamp Duty Land Tax | £0–£50,000+ depending on purchase price |
| Estate agent fee | £3,000–£12,000 |
| Conveyancing (sell + buy) | £2,000–£4,000 |
| Survey on new property | £500–£1,500 |
| Removal | £1,000–£4,000 |
| Immediate works (typical) | £5,000–£20,000 |
| Total (typical) | £15,000–£60,000+ |
When extending makes more financial sense
Extending is often the better financial option when:
- The extension cost is significantly less than the total transaction costs of moving.
- The local market means that a bigger house in the same area costs £100,000–£200,000 more (plus all the transaction costs on top).
- You want to stay in the same area — for schools, community or convenience — and the bigger houses available locally are limited or expensive.
- The extension can deliver the specific space you need (a larger kitchen-diner, a ground-floor bedroom).
When moving makes more sense
Moving is often the better option when:
- You need more space than extending could reasonably deliver (for example, you need a fifth bedroom and a double garage, and there is no planning headroom or garden space for the required extension).
- You want to move location — for work, schools or lifestyle reasons — and an extension cannot address that.
- The property is at or above the ceiling price for its street, so extending would not add value and the capital is better deployed as equity in a new purchase.
- The condition of the existing property means that the cost of extending and renovating together exceeds the cost of buying something newer.
The disruption factor
An extension involves living through a building project, typically for 8–20 weeks on site, with dust, noise and restricted access to parts of the house. Moving involves weeks of preparation, sale negotiations and chain management, with the risk of a collapsed chain. Both involve disruption — neither is without stress. Families with young children often find extending more manageable because the school run and community remain unchanged. This page is general information and not financial advice; always take professional guidance for your specific situation and check current stamp duty rates on GOV.UK.
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Frequently asked questions
Is it cheaper to extend or move house in the UK?
In many cases, extending is cheaper in total cost — particularly when stamp duty, agent fees and conveyancing on a move are included. The comparison depends on property values, extension type and what space you need. Always run the numbers for your specific situation.
What are the transaction costs of moving house?
Typically £15,000–£60,000+ including stamp duty, estate agent fee, conveyancing, surveyor, removal and immediate works on the new property. The largest single item is usually stamp duty.
How much stamp duty would I pay on a £500,000 house?
At 2026 standard residential SDLT rates, approximately £12,500. The rate structure changes periodically — always check the current rates on the GOV.UK stamp duty calculator before making any financial decision based on SDLT.
Can I extend and then move later?
Yes, and a well-executed extension with building regulations completion certificate and planning consent in place can make the property easier to sell and potentially increase its value. An extension built without proper consents can have the opposite effect — see our planning permission guide.
Sources & further reading
- GOV.UK — Stamp Duty Land Tax: rates, thresholds and the SDLT calculator
- RICS — Residential valuations and the financial case for extending vs trading up
- Planning Portal — Planning permission and building regulations for extensions
- LABC — Building regulations completion certificates and their significance on sale
This is general information about house extensions in England and is not planning, structural, legal or financial advice. Costs, timescales and outcomes vary with your design, ground conditions, specification and local authority. Always obtain written quotes and verify planning and building regulations requirements with your local planning authority before committing to any works.