How to extend your lease: a step-by-step guide

Flat owners with a short lease are learning the hard way that time really is money. New analysis from House Buyer Bureau, reported this month, found that flats with 60 years or less left on the lease are selling for an average of £48,250 less than comparable properties, a discount of over 22 percent. In Yorkshire and the Humber, the gap widens to more than 35 percent.

If you own a leasehold flat, or you're thinking about buying one, understanding how lease extension works, and when to act, could save you a significant sum. Here's what a short lease means for your property, and the steps to sort it out.

What counts as a short lease

There's no single legal cut-off, but a few numbers matter more than others. Below 80 years remaining, you'll usually have to pay marriage value: a share of the extra value your flat gains once the lease is extended, on top of the standard premium. That alone can add thousands to the cost. Below around 70 years, many mortgage lenders start to get twitchy, and below 60, some won't lend on the property at all, which shrinks your pool of buyers to cash purchasers only.

For background on how leasehold ownership works more generally, our explainer on leasehold property and ground rent covers the basics.

Why a short lease hits your asking price so hard

A shrinking lease is a shrinking asset: the fewer years left, the closer the flat gets to reverting to the freeholder with no compensation to the leaseholder. Buyers know this, so they factor in both the cost of extending later and the hassle of doing it. Add in the restricted mortgage market for short leases, and sellers end up competing for a smaller pool of buyers, which pushes prices down further still. House Buyer Bureau's analysis put the average short lease flat at £170,201, against £218,451 for flats generally, a gap that's rarely closed by a lick of paint or a good set of listing photos.

How to extend your lease: step by step

1. Check you're eligible. You'll usually qualify if you've owned the flat as a leaseholder and the lease was originally granted for more than 21 years. The old rule requiring two years of ownership before you could apply was scrapped in January 2025, so new owners no longer have to wait.

2. Get a valuation. A RICS-qualified surveyor with leasehold extension experience will calculate the likely premium, factoring in ground rent, years remaining, and your flat's value. This figure is your starting point for negotiation.

3. Instruct a solicitor. Lease extension is a specialist area, so look for a solicitor who handles it regularly. They'll prepare the formal notice and guide you through the legal process.

4. Serve a Section 42 notice. This formal notice, served under the Leasehold Reform, Housing and Urban Development Act 1993, sets out your proposed premium and starts the statutory clock.

5. Wait for the counter-notice. Your freeholder has two months to respond, either accepting your terms, proposing different ones, or disputing your right to extend altogether.

6. Negotiate the premium. Most cases settle through negotiation between surveyors. If you can't agree, either side can apply to the First-tier Tribunal to have the premium decided.

7. Complete and register. Once terms are agreed, your solicitor completes the new lease and registers it with the Land Registry. Under the current statutory process, a successful extension adds 90 years to what's left on your lease, at a peppercorn (zero) ground rent.

What it actually costs

Costs vary widely depending on your flat's value and years remaining, but recent market analysis puts the premium at upwards of £12,500 for a lease close to 100 years, rising past £33,000 for leases under 60 years, once marriage value is factored in. On top of the premium, you'll typically also cover your own legal and valuation fees, plus your freeholder's reasonable costs for theirs. For the wider process of buying or selling a leasehold flat, our step-by-step guide to conveyancing and our note on service charges are useful reading alongside this.

Extend now, or leave it to your buyer?

If you're planning to sell, this is the real decision point. Extending before you market the flat widens your buyer pool to include mortgaged buyers, and lets you set an asking price that reflects a long lease rather than a discounted one. The trade-off is time and upfront cost: the statutory process typically takes a few months from notice to completion, and you'll need to fund the premium and fees before you see any return.

Selling with the short lease intact and letting your buyer extend afterwards is faster and avoids that upfront outlay, but you'll take the hit in your sale price instead. If you're weighing up your options for getting the best price either way, our guide on increasing your property's value before selling is a good starting point, and our ultimate guide to selling your house covers the process end to end.

If you're a landlord with a short lease flat

Plenty of buy-to-let flats are held on leasehold titles, and the same squeeze applies whether you're planning to sell or refinance. A shortening lease can limit your remortgaging options as much as it limits a buyer's, so it's worth checking years remaining as part of your annual portfolio review, not just when a sale is on the cards.

If you decide to extend and keep the flat let out, our fully managed lettings service can take the day-to-day off your hands while the extension goes through, or our tenant find service can help you re-let between tenancies. If you'd rather sell up, our team can help you sell your home and talk through whether extending first makes sense for your particular flat.

Reform is coming, but it isn't law yet

The Leasehold and Freehold Reform Act 2024 promises bigger changes: extensions of 990 years instead of 90, and the scrapping of marriage value altogether, which would make extending a short lease considerably cheaper. So far, though, only one part of it is actually in force, the removal of the two-year ownership wait. The rest depends on secondary legislation and a further draft bill that's still working its way through Parliament, and could realistically be years away.

We've covered the detail of what's changed and what hasn't in our leasehold reform 2026 explainer. The short version for now: if your lease is getting short, it's rarely worth waiting for reform that hasn't arrived, especially since marriage value only gets more expensive the fewer years you have left.

The practical takeaway

If your lease has dropped below 80 years, get a valuation now rather than later. The cost of extending only rises as the years tick down, and a short lease can quietly cap your sale price long before you're ready to move. If you're weighing up whether to extend or sell as you are, our team can help you sell your home at a fair, flat fee, and talk you through which route suits your situation.