Lease Extension Calculator
Estimate your lease extension premium in seconds. Our free lease extension calculator gives you a rough guide to costs based on your property value and remaining lease length.
Calculate Your Lease Extension Cost
The estimated market value of your flat with its current lease.
Check your lease document or Land Registry title for the exact term remaining.
The annual ground rent you currently pay. Enter 0 if peppercorn.
How Does a Lease Extension Calculator Work?
A lease extension calculator estimates the premium you would need to pay to your freeholder to extend your lease. The calculation is based on the established valuation methodology used by the First-tier Tribunal and specialist leasehold valuers across the UK.
The premium is made up of three components: the capitalised value of the ground rent the freeholder will lose during the extended term, the diminution in the value of the freeholder's reversion (their future right to the property when the lease expires), and marriage value if the lease has fewer than 80 years remaining.
Our calculator uses standard capitalisation rates and relativity assumptions to produce a rough estimate. The actual premium can vary significantly depending on your specific lease terms, ground rent review clauses, and local market conditions. For a formal valuation, we recommend instructing a qualified surveyor with experience in lease extension work.
Key Factors Affecting Your Lease Extension Cost
Remaining Lease Length
The shorter the lease, the more expensive the extension. Costs rise sharply once the lease drops below 80 years due to marriage value.
Property Value
Higher property values mean higher premiums because the freeholder reversion and any marriage value are both calculated as a proportion of the flat value.
Ground Rent
Higher ground rents increase the premium because the freeholder loses a larger income stream. Escalating ground rent clauses can add significantly to costs.
Marriage Value
Only applies to leases below 80 years. Represents half the uplift in property value from extending the lease. The 2024 reforms abolish this once enacted.
Capitalisation Rate
The discount rate used to calculate the present value of the freeholder future income. Typically 5% to 6% for residential properties, but can vary.
Relativity
The ratio of the value of a flat with its existing short lease to the value of the same flat with a long lease. More important for leases under 80 years.
Frequently Asked Questions About Lease Extensions
How accurate is a lease extension calculator?
A lease extension calculator provides a rough estimate based on standard valuation methodology. The actual premium depends on many variables including the specific lease terms, ground rent structure, yield rate, and local property market conditions. For an accurate figure, you should instruct a specialist leasehold surveyor who can prepare a formal valuation. Our team can recommend accredited valuers experienced in lease extension work.
What is the 80 year rule for lease extensions?
When a lease drops below 80 years remaining, an additional element called marriage value becomes payable as part of the premium. Marriage value represents the increase in the property value that results from extending the lease. The freeholder is entitled to a share of this uplift, which can add thousands of pounds to the cost. The Leasehold and Freehold Reform Act 2024 abolishes marriage value, though this provision is being implemented in stages.
How much does a lease extension cost in the UK?
The total cost of a lease extension includes the premium paid to the freeholder, your solicitor fees (typically one thousand to two thousand pounds), the freeholder legal and valuation costs (which you must pay), and your own surveyor fees. For a flat worth two hundred and fifty thousand pounds with 75 years remaining, the premium alone could be fifteen thousand to twenty-five thousand pounds. Properties with shorter leases or higher values will cost significantly more.
Can I use a lease extension calculator for HMRC purposes?
HMRC provides its own lease extension calculator for determining the capital gains tax implications of a lease extension. The HMRC leasehold calculator uses a different methodology based on prescribed tables in Schedule 8 of the Taxation of Chargeable Gains Act 1992. For tax purposes, always use the official HMRC calculator and seek advice from a qualified accountant.
How long does a lease extension take to complete?
A statutory lease extension typically takes six to twelve months from start to finish. The process involves obtaining a valuation, serving a Section 42 notice, waiting for a counter-notice, negotiating the premium, and completing the legal work. If the premium cannot be agreed, either party can apply to the First-tier Tribunal, which adds several months. An informal extension negotiated directly with the freeholder may be quicker.
What are the new lease extension laws in 2024-2025?
The Leasehold and Freehold Reform Act 2024 extends the standard lease extension term from 90 years to 990 years, abolishes marriage value from the premium calculation, removes the two-year ownership requirement, reduces ground rent on extended leases to a peppercorn, and introduces a simplified valuation methodology. These reforms are being implemented in stages, and some provisions may not yet be in force.
Need Accurate Lease Extension Advice?
Our leasehold specialists can guide you through the entire lease extension process, from initial valuation to completion. Get expert advice tailored to your property.