The cost of a lease extension for a flat, and how the process works

A statutory lease extension on a flat in England and Wales adds 90 years to whatever is left of your lease and reduces the ground rent to a peppercorn, meaning nothing is payable. You pay the landlord a premium for that, and under the law as it stands you also pay their reasonable valuation and legal costs on top of your own. Valuation turns on the specific terms of your lease, so treat what follows as general information rather than advice.

How the statutory route runs

The right comes from the Leasehold Reform, Housing and Urban Development Act 1993, and it applies to flats rather than houses, worth checking against our guide to freehold vs leasehold if you're not sure which you own. You start the claim by serving a section 42 notice on your landlord, which is the formal notice that opens the process and fixes the valuation date.

Since 31 January 2025 you no longer need to have owned the flat for two years before serving that notice. A buyer can now serve on the day they complete, which matters if you're buying a flat with a short lease and can't afford to wait.

The landlord replies with a counter-notice by the date set in your notice, and the two sides negotiate the premium. If they can't agree, the First-tier Tribunal (Property Chamber) decides it in England, and the Leasehold Valuation Tribunal does so in Wales.

The three parts of the premium

The first is the capitalised ground rent. The landlord loses the rent for the remainder of the current term, so the valuer works out what that income stream is worth in today's money.

The second is the reversion. This is the value of the landlord getting the flat back when the lease ends, pushed 90 years further into the future and therefore worth much less today.

The third is marriage value, the increase in the combined value of your interest and the landlord's interest created by the extension. The Leasehold Advisory Service explains that the law splits marriage value equally between leaseholder and landlord, and that it's only payable where the lease has 80 years or fewer remaining on the date the section 42 notice is served.

Why a lease under 80 years costs sharply more

Above 80 years marriage value drops out of the sum entirely, so the price rises in a step rather than along a smooth curve. The figures below are illustrative, chosen to show the arithmetic. Only a valuer can produce real ones for your flat.

Take a flat worth £242,000 with 76 years left, and £285,000 once extended. Say the landlord's interest is worth £9,400 now and £300 after the extension.

Combined value before the extension is £242,000 plus £9,400, which is £251,400. Combined value after is £285,000 plus £300, which is £285,300. The increase is £33,900, and half of that, £16,950, goes to the landlord.

The landlord also loses £9,100 of value in their own interest, being £9,400 less £300. Adding the two gives a premium of about £26,050. Had the same flat had 81 years left, the marriage value share would have been nil and the premium would have been roughly the £9,100 alone. If you're weighing up whether to sell rather than extend, our guide to selling a leasehold flat covers how a short lease affects that decision too.

What the 2024 Act changes, and what is in force

The Leasehold and Freehold Reform Act 2024 received Royal Assent in May 2024, but most of it still waits on secondary legislation. The government's own plain English explainer on extending your lease, updated on 7 September 2026, uses the future tense throughout and says the changes still need regulations.

A consultation on the deferment and capitalisation rates that will drive the new calculation was due to close on 23 September 2026, but the government extended it by four weeks on 7 September 2026, so it's now open until 21 October 2026. Those rates then have to be set in regulations, and the government has said it will fix technical defects in the 2024 Act through a forthcoming Commonhold and Leasehold Reform Bill. A group of freeholders lost a High Court challenge in October 2025, and the Court of Appeal granted them permission to appeal in April 2026, with a hearing expected late this year or early next.

So anyone telling you marriage value has been abolished is wrong. It's payable on every sub-80-year extension completing today.

Fees, and the decision about timing

You pay your own valuer and solicitor, plus the landlord's reasonable valuation and legal costs, and our guide to conveyancing fees gives a sense of what solicitor costs typically run to on a transaction like this. The government describes the pending reform to that rule as saving leaseholders hundreds or even thousands of pounds, which gives you the scale of what you're currently carrying.

If your lease sits just above 80 years, waiting is the expensive option. Dropping below the threshold before you serve adds a marriage value share, and no future reform will refund it to you.

If you're budgeting for an extension alongside a purchase or sale, compare quotes for leasehold conveyancing work before you instruct anyone.