Calculate Your Lease Extension Premium Instantly
Free leasehold enfranchisement calculators. Instant estimates using the 5% deferment rate from Sportelli — no registration required.
🇺🇸 Also used by Americans buying UK property and Hawaii leasehold condo owners — see our complete US buyer guide →
Buying as a non-UK resident? Check your Stamp Duty Land Tax with our free SDLT calculator →
Your estimate in under 60 seconds
The same statutory valuation approach that surveyors use and tribunals apply, with the working shown.
Enter Details
Property value, lease length, and ground rent — that’s all we need.
We Calculate
Our calculator applies the 5% deferment rate and published Gerald Eve relativity figures instantly.
See Breakdown
Reversion, ground rent cap, marriage value if applicable, plus total professional fees.
Take Action
Share your estimate with your surveyor or solicitor and start the process.
The most complete free tool in the UK
Transparent Formula
We use the Deferment Rate methodology established by the Lands Tribunal in Sportelli — the same formula used by professional valuers.
Marriage Value Alert
Our calculator automatically flags marriage value when your lease is under 80 years and shows exactly how much it adds to your premium.
Total Cost Breakdown
See premium components plus estimated solicitor and surveyor fees — budget the full outlay, not just the headline figure.
2026 Rates
All calculations reflect the current 5% deferment rate, 2026 relativity tables, and guidance under the Leasehold Reform Act 2024.
Private & Free
No signup, no credit card. Your calculation stays in your browser. We never store property details without your consent.
Mobile Ready
Use our calculator on any device. Share results directly with your solicitor or surveyor via email or WhatsApp.
Understand your leasehold rights
In-depth guides covering everything from the 80-year rule to collective enfranchisement and the 2024 reforms.
What is Leasehold Enfranchisement? A Complete UK Guide 2026
Understand what leasehold enfranchisement means, your rights under UK law, and the two main routes: lease extension and freehold purchase.
The 80-Year Lease Rule: Why It Could Cost You Thousands
The 80-year lease threshold is the single most important milestone for any UK leaseholder. Learn how marriage value works and why crossing this line can double your extension cost overnight.
Leasehold Reform Act 2024: Everything You Need to Know
A comprehensive breakdown of the Leasehold and Freehold Reform Act 2024 — what changed, what is being phased in, and how it affects your premium.
Frequently Asked Questions
Our calculator applies the statutory valuation approach using the 5% deferment rate from Sportelli and published relativity figures, and shows its working. It is an estimate, not a valuation: actual premiums depend on local comparable evidence and negotiation, and can differ materially. Always instruct a specialist before serving a section 42 notice.
Once a lease falls below 80 years, marriage value becomes payable — potentially doubling or tripling your total extension cost. Above 80 years, marriage value is not payable. This is the single most important financial milestone in leasehold enfranchisement.
The Act proposes to abolish marriage value and extend the standard extension to 990 years. Many provisions require secondary legislation before coming into force. Our calculator uses the current the statutory valuation method.
The statutory process typically takes 6–12 months for an uncontested case. If the matter goes to the First-tier Tribunal, add 12–18 months.
Ideally when your lease reaches 90 years — giving you time to complete comfortably before crossing the 80-year marriage value threshold. If you are already below 85 years, act immediately.
Buying UK Leasehold Property as an American?
Get our free 10-question pre-purchase checklist, or go deeper with the complete 30-page guide.
Get Leasehold Reform Alerts
We’ll notify you when 2024 Act provisions come into force, new rates are published, and when landmark Tribunal decisions affect your premium.