📚 US Buyer Guide — Full Series
→ UK Leasehold for Americans: The Complete Guide → What Is Leasehold Property in the UK? → Leasehold vs Freehold: US Translation Guide → How Much Does a Lease Extension Cost? → Share of Freehold Explained → Ground Rent Explained → UK Property Buying Process for Americans → London Property Taxes for AmericansLease extension costs are often the biggest financial surprise for UK flat owners — and for American buyers in particular, who have no reference point for how they are calculated. This guide breaks down every cost component, provides worked examples at real property values, and shows you how to use our free calculator to get your specific estimate in seconds.
📚 US Buyer Guide — Full Series
→ UK Leasehold for Americans: The Complete Guide → What Is Leasehold Property in the UK? → Leasehold vs Freehold: US Translation Guide → The 80-Year Lease Rule Explained → How Much Does a Lease Extension Cost? → Share of Freehold Explained → Ground Rent Explained → UK Property Buying Process for Americans → London Property Taxes for AmericansThe total cost of extending a lease in the UK has two distinct components: the premium paid to the freeholder, and the professional fees paid to your solicitor, surveyor, and the freeholder's professionals.
The lease extension premium is not arbitrary. It is calculated using a formal valuation methodology developed by the Royal Institution of Chartered Surveyors (RICS) and confirmed in landmark Tribunal decisions. The premium has three components:
Our free calculator computes all three components for any lease length, property value, and ground rent — using the same RICS deferment rate (5%) and standard relativity tables as professional surveyors.
| Property Value | Lease Remaining | Ground Rent | Est. Premium | Marriage Value | Total inc. Fees |
|---|---|---|---|---|---|
| £300,000 | 90 years | £100 | £2,500–£4,000 | £0 | £6,500–£9,000 |
| £400,000 | 85 years | £200 | £5,000–£8,000 | £0 | £9,000–£14,000 |
| £500,000 | 79 years | £250 | £14,000–£20,000 | £8,000–£13,000 | £19,000–£26,000 |
| £600,000 | 75 years | £300 | £25,000–£36,000 | £16,000–£24,000 | £30,000–£42,000 |
| £700,000 | 70 years | £350 | £38,000–£56,000 | £26,000–£38,000 | £44,000–£63,000 |
| £800,000 | 65 years | £400 | £58,000–£85,000 | £42,000–£62,000 | £64,000–£92,000 |
Estimates use RICS 5% deferment rate and standard relativity graph. Professional fees estimated at £4,000–£7,000. Use our free calculator for your specific numbers.
| Cost Item | Who Pays | Typical Range |
|---|---|---|
| Extension premium | You | £2,500–£85,000+ depending on lease and value |
| Your RICS surveyor | You | £750–£1,500 |
| Your specialist solicitor | You | £1,500–£3,000 |
| Freeholder's surveyor | You (legally required) | £750–£2,000 |
| Freeholder's solicitor | You (legally required) | £750–£2,000 |
| Land Registry fee | You | £20–£500 |
| Total professional costs | You | £4,000–£9,000 on top of the premium |
Most leaseholders — and almost all American buyers — are genuinely shocked to discover that they must pay the freeholder's surveyor and solicitor costs on top of their own. This is a statutory requirement under the 1993 Act. You are legally obliged to pay the freeholder's reasonable costs of the extension process.
"Reasonable" is the operative word. If the freeholder attempts to charge excessive professional fees, you can challenge them at the First-tier Property Tribunal. But in a normal case, budget £1,500–£4,000 for the freeholder's professional costs — these are unavoidable.
Our free calculator uses the same RICS deferment rate and relativity tables as professional surveyors. Enter your property value, lease length, and ground rent to get an instant estimate — no sign-up required.
Free Lease Extension Calculator
Instant RICS-methodology estimate. No sign-up, no fees, no spam.
Calculate My Premium →🇺🇸 American buying a UK flat?
The American's Guide to Buying a UK Leasehold Flat
30 pages. Ground rent, the 80-year rule, marriage value, stamp duty, US tax reporting and the 2026 reforms — all in plain American English.
The total cost of a lease extension has two main components: the premium paid to the freeholder (calculated using RICS methodology) and professional fees. On a £400,000 flat with 80+ years remaining, the premium typically ranges from £5,000 to £12,000. Below 80 years, marriage value adds significantly — the same flat at 72 years could cost £25,000–£40,000 in premium alone. Professional fees typically add £4,000–£9,000 on top.
Professional fees include: your RICS surveyor (£750–£1,500), your specialist leasehold solicitor (£1,500–£3,000), the freeholder's surveyor whose costs you must pay (£750–£2,000), the freeholder's solicitor whose costs you must also pay (£750–£2,000), and Land Registry fees (£20–£500). Total professional fees typically run £4,000–£9,000 in addition to the premium itself.
Yes — this surprises most buyers. Under the 1993 Act, you are legally required to pay the freeholder's reasonable professional costs (surveyor and solicitor) as part of the lease extension process. These are not negotiable in principle, though you can challenge unreasonable amounts. Budget £1,500–£4,000 for the freeholder's professional costs on a standard extension.
Yes. The premium is calculated using RICS methodology but there is often a range between the leaseholder's surveyor's figure and the freeholder's surveyor's figure. Most cases (around 75%) settle by negotiation between the two surveyors. If no agreement is reached within 6 months of the counter-notice, either party can apply to the First-tier Property Tribunal to set the premium.
Usually not on a standard statutory lease extension under the 1993 Act. However, SDLT may apply in some circumstances — always confirm with your solicitor before exchange. Lease extension premiums do not attract SDLT in the majority of cases.
The shorter the lease, the higher the premium — because the freeholder's reversionary interest (the right to get the property back) is worth more with fewer years remaining, and because marriage value kicks in below 80 years. Our free calculator shows the premium for any lease length and property value instantly.
We'll notify you when key 2026 reform provisions take effect — including marriage value abolition and the ground rent cap.
Estimate your lease extension premium instantly using RICS methodology.
Calculate Now →General information only. Not legal advice. Consult a RICS surveyor and specialist solicitor before acting.
We'll notify you when 2026 Act provisions come into force, new rates are published, and key decisions are made.