What might the lease extension cost?
A guide range for the statutory route (90 more years at a peppercorn rent), with the three parts of the premium shown separately, so you can see what is driving your number and what the 80-year threshold does to it.
What the remaining lease length means
Lease length affects mortgage choice, resale and the likely extension premium. Lenders set their own policies, so these are practical risk bands rather than universal lending rules.
90 years or more
Usually the least urgent position for a buyer. The lease is still shortening, but there is time to plan and a wider choice of lenders is normally available.
80 to 89 years
The 80-year threshold is close enough to affect the purchase decision. Starting a statutory claim while the lease remains at 80 years or above avoids marriage value under current law.
Below 80 years
Marriage value forms part of the statutory premium. The cost generally rises faster as the term shortens, so the likely extension bill belongs in the purchase negotiation.
Around 70 years or fewer
Mortgage choice can narrow materially and resale becomes harder. Policy differs between lenders, so a broker, conveyancer and leasehold valuer should check the actual lease and the proposed lender's requirements before exchange.
How a statutory lease extension works today
This calculator models the law currently in force for a qualifying flat owner. It is not a prediction of the future valuation method.
The term and ground rent
The current statutory route adds 90 years to the remaining term and reduces ground rent to a peppercorn for the extended period.
The premium
The price reflects the ground rent the freeholder gives up, the deferred right to the flat and, below 80 years, half the value released by extending the lease.
The evidence
Relativity, ground-rent terms and the condition of the actual lease can move the figure substantially. A RICS Registered Valuer uses comparable and tribunal evidence rather than a generic curve alone.
The process and other costs
A conveyancer checks eligibility and serves the formal notice. Valuation and legal fees sit outside the premium, including the freeholder's reasonable costs under current law.
What the 2024 reforms may change
The valuation reforms are not yet in force. On 15 July 2026 the government opened a consultation on the deferment and capitalisation rates that will drive the new standard valuation method. It says secondary legislation and fixes through a forthcoming Bill are still required, while the High Court decision is under appeal. No commencement date has been announced.
Marriage value
The Act provides for it to be removed, which could reduce premiums on leases at or below 80 years once commenced.
A 990-year extension
The intended standard term is 990 years at a peppercorn ground rent, rather than the current 90-year addition for flats.
Valuation rates
Government-set deferment and capitalisation rates will replace rates argued from valuation and court evidence.
Process costs
The stated intention is that leaseholders normally pay their own costs, with limited exceptions still being consulted on.
These are intended future changes, not inputs to the range above. The calculator continues to use the current statutory basis until the relevant provisions commence.
Ground rent needs its own check
The calculator assumes a level ground rent. Older leases can contain clauses that change the cost, mortgageability and valuation of the flat even before an extension is considered.
Rising or doubling rent
A rent that doubles periodically or rises with inflation needs to be modelled from the actual review schedule. A single annual figure cannot represent it safely.
Read the lease, not the sales details
Ask the conveyancer to check the term, review clause, service-charge provisions and any restrictions before exchange. A summary from the seller or agent is not a substitute.
Current official guidance
- Leasehold enfranchisement valuation rates consultationMinistry of Housing, Communities and Local Government, published 15 July 2026.
- Government plain-English explainerThe intended reforms, the steps still required and the position of the court appeal.
- LEASE: the Leasehold Advisory ServiceFree, independent guidance tailored to leaseholders in England and Wales.
Negotiating a lease extension?
The freeholder will have a valuer. The premium range above is where the negotiation happens, and the difference between its ends is usually many times the valuation fee. A Red Book valuation from an RICS Registered Valuer is the document that argues your end of it.
Buying a leasehold flat? A survey covers the building; the lease length above tells you what else you are really buying.
Common questions
Has marriage value been abolished yet?
Not yet. The Leasehold and Freehold Reform Act 2024 provides for marriage value to be removed, but those valuation provisions are not in force. The government opened its consultation on deferment and capitalisation rates on 15 July 2026 and says regulations and further primary legislation are still needed. The High Court decision is also under appeal. Until commencement, extensions are valued under current law, including marriage value below 80 years.
Why does the 80-year mark matter so much?
Below 80 years the freeholder is entitled to half the value the extension releases — marriage value — and the premium steps up sharply as the lease shortens. A lease at 82 years is genuinely cheaper to extend than the same lease at 78. If you are buying with a lease in the low 80s, the clock is part of the price.
Should I wait for the reforms before extending?
That is a genuine judgement call, not a calculator output. The government has not announced a commencement date for the new valuation method. Waiting may reduce the premium, but every year that passes shortens the lease and a lease crossing below 80 years attracts marriage value under current law. Anyone near the threshold should take specialist legal and valuation advice rather than rely on an unknown implementation date.
What costs come on top of the premium?
Under the current statutory route you normally pay your own valuation and legal fees and the freeholder’s reasonable ones — commonly £3,000 to £5,000 in total on a straightforward case. The government intends most leaseholders to pay only their own process costs under the reforms, subject to limited exceptions, but those changes are not yet in force.
Is this an official valuation?
No. It is a guide range from standard assumptions so you can see the shape of the cost. A formal valuation by an RICS Registered Valuer analyses the actual lease terms, ground rent schedule and local relativity evidence, and is what you negotiate or go to tribunal with.