Costs

Lease extension cost explained

A short lease can make a flat hard to mortgage and expensive to fix later. Knowing what an extension costs, and understanding the 80-year cliff edge, protects you before you buy and helps you negotiate the right price. This guide breaks down the premium, the fees and the reforms reshaping the system.

Last reviewed 26 June 2026

In short

Extending a lease costs a premium paid to the freeholder plus professional fees (valuer and solicitor for both sides), commonly totalling a few thousand to tens of thousands of pounds depending on the flat's value, the ground rent and how many years are left. The crucial threshold is 80 years: once a lease drops below 80 years, 'marriage value' is added, sharply increasing the cost, and mortgage lenders become reluctant to lend. Recent leasehold reform aims to make extensions cheaper and longer (up to 990 years) and remove marriage value, but always get a professional valuation for your specific flat.

How a lease extension premium is worked out

The premium is the price you pay the freeholder for the extra years. It is calculated from three main ingredients: the value of the flat, the ground rent payable, and how many years remain on the lease. The fewer years left, the more the freeholder loses by granting an extension, so the premium climbs steeply as the lease shortens.

On top of the premium you pay professional fees. Under the current statutory route you usually cover both your own and the freeholder's reasonable valuation and legal costs, which is why extending a lease is rarely a small bill.

Roughly what to expect (illustrative only)

These are broad illustrations. Premiums vary enormously by location and flat value, so always get a specialist valuation.

Years remainingMarriage value?Relative cost
90+ yearsNoLowest, often a few thousand pounds plus fees
80 to 89 yearsNoModerate, rising as 80 years approaches
Just under 80 yearsYesJumps sharply once marriage value applies
60 to 70 yearsYesHigh, often tens of thousands
Under 60 yearsYesVery high, and hard to mortgage

Reform proposals aim to remove marriage value, but until changes are fully in force, the 80-year threshold still bites.

What drives the cost

  • Years remaining on the lease, the shorter, the more expensive.
  • Whether the lease is above or below 80 years (marriage value).
  • The value of the flat and the ground rent payable.
  • Professional fees, you usually pay both sides' valuer and solicitor.
  • Whether you use the statutory route or negotiate informally with the freeholder.

Statutory route vs informal agreement

Statutory routeInformal (voluntary) deal
Extra years90 years on top of existing (currently)Negotiable, whatever is agreed
Ground rentReduced to a peppercorn (nil)May remain or even increase
Price controlSet by formula, can go to tribunalWhatever freeholder will accept
CertaintyHigher, legally backedLower, depends on goodwill

Informal deals can be quicker but may leave you with ongoing ground rent or worse terms. Take legal advice before agreeing.

Beware the 80-year threshold

Below 80 years, marriage value makes extending far more expensive and lenders may refuse a mortgage. If buying a flat near 80 years, factor the extension into your offer or ask the seller to start the process before completion.

Leasehold reform and what it means for you

The Leasehold and Freehold Reform Act sets out major changes: a standard extension term of 990 years, the removal of marriage value, and an end to the two-year ownership wait before you can extend. These reforms are being introduced in stages, with detailed rules following secondary legislation.

Until the changes are fully in force, the existing rules still apply, so do not assume a cheaper deal is automatically available yet. If you are buying a short-lease flat, get current advice and a specialist valuation so you price the extension correctly into your offer.

Common questions

How much does it cost to extend a lease?

It ranges from a few thousand to tens of thousands of pounds, depending on the flat's value, the ground rent and years remaining. You also pay professional fees for valuers and solicitors on both sides. Always get a specific valuation.

Why is an 80-year lease a problem?

Once a lease falls below 80 years, 'marriage value' is added to the extension premium, sharply raising the cost, and many mortgage lenders won't lend on it. This makes short-lease flats harder to buy and sell.

Can I extend the lease as soon as I buy?

Under current rules you generally need to have owned the flat for two years before using the statutory route, though a seller can serve notice and assign it to you at completion. Reforms aim to remove the wait, so take legal advice for your situation.

What is marriage value?

Marriage value is the extra value created by extending a short lease, which the law currently requires you to share with the freeholder once the lease is below 80 years. Removing it is a key aim of leasehold reform.

Who pays the freeholder's costs?

Under the statutory route you usually pay your own and the freeholder's reasonable valuation and legal fees. This is one reason extensions cost more than the premium alone.

How long does a lease extension take?

A statutory extension typically takes several months from serving notice to completion, longer if the premium is disputed and goes to the First-tier Tribunal. Informal deals can be quicker but offer less protection.

Should I extend before selling or buying?

If you're selling a short-lease flat, extending first (or serving notice) can widen the buyer pool and lift the price. If you're buying, it's often better to ask the seller to start the process so you inherit the benefit.

Can I buy the freehold instead?

In some cases, yes. If enough leaseholders in a block act together they may be able to buy the freehold (collective enfranchisement) or set up a right to manage, which can be more cost-effective than repeated extensions.

Sources

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