Use this calculator to get an indication of the premium payable to your landlord for a statutory lease extension — the 90-year extension with the ground rent reduced to a peppercorn that most leaseholders of flats are entitled to claim.
If you do not have the lease to hand, an official copy of your title and lease can be obtained from HM Land Registry for a few pounds.
Calculated under Schedule 13 to the Leasehold Reform, Housing and Urban Development Act 1993
Indicative premium range
—
Relativity is derived from a curve based on the Savills 2015 and Gerald Eve 2016 unenfranchiseable graphs. This is a simplified, non-binding estimate. Actual premiums depend on detailed valuation, comparable evidence, ground rent terms, improvements, rights and negotiation. Development value is not included. For a formal figure please obtain a specialist valuation from an RICS Registered Valuer.
Don’t know your lease length?
The calculator above needs your unexpired term. If you do not have it to hand, the Leasehold Advisory Service — the government-funded advice body — offers a free lease length check for flats and houses in England and Wales. You will need the property address and an email address.
It saves buying a Land Registry title register, which costs a few pounds and takes longer. Once you have the term, come back and enter it above.
A note on estimates
LEASE also provides a premium estimate. Like ours, it is indicative only and should not be used as a basis for negotiation. Where a notice has been served or terms are being agreed, a formal valuation from an RICS Registered Valuer is what the other side will expect.
The Leasehold Advisory Service is an independent body funded by the Ministry of Housing, Communities and Local Government. Blakes is not affiliated with LEASE and is not responsible for the content of external sites.
This is an indication, not a valuation. The figure produced is a guide to the order of magnitude of the premium. It is not a formal valuation, it is not advice, and it should not be relied on when serving a notice or agreeing terms with a landlord.
It excludes the professional and statutory costs of a claim. The premium is only part of what you pay. See the breakdown below.
A statutory claim commits you to a figure and to statutory deadlines. Before serving a section 42 notice you should take advice from an RICS Registered Valuer who has considered the lease, the ground rent provisions, comparable evidence and the particular building.
The premium for a statutory lease extension is not a single number pulled from a table. It is the sum of what the landlord gives up, and the calculator models the same three components a valuer would.
Extending your lease reduces the ground rent to a peppercorn — nil. The landlord loses that income for the remainder of the existing term. That future income stream is capitalised to a present-day figure using a yield, and the higher the rent and the longer it had to run, the larger this element becomes.
At the end of the lease the flat reverts to the landlord. Adding 90 years pushes that date much further into the future, so the value of the landlord’s right to get the flat back falls. The difference between the value of that right before and after the extension forms the second component. It is calculated using a deferment rate.
Where the unexpired term is below 80 years, the new lease creates value that neither the leaseholder nor the landlord holds separately beforehand. Under the law as it currently stands that uplift is shared equally between the two. Above 80 years, marriage value does not apply at all — which is why the figure jumps sharply as a lease crosses that threshold.
Every one of those steps rests on a judgement: the capitalisation yield applied to the ground rent, the deferment rate applied to the reversion, and the relativity between the short lease value and the long lease value. This calculator applies conventional assumptions. A valuer would select them for your specific building, location, lease terms and the evidence available — and it is precisely these assumptions that the two surveyors negotiate over.
A calculator applies standard assumptions to three numbers. A valuation considers the actual lease, the actual building and the actual evidence. The gap between the two matters most in these situations:
In each of these cases the calculator will still produce a number. It just will not be the right one.
The calculator estimates the premium only — the sum paid to the landlord. A statutory claim carries further costs, and you should budget for all of them.
| Cost | Who pays | Notes |
|---|---|---|
| Premium | You | The figure this calculator estimates |
| Your valuer’s fee | You | Fixed fee agreed before instruction |
| Your solicitor’s fee | You | Preparing and serving the notice, and completing the new lease |
| Landlord’s valuation fee | You | Statutory; must be reasonable and can be challenged |
| Landlord’s legal fees | You | Statutory; must be reasonable and can be challenged |
| Land Registry fees | You | Registering the new lease |
| Stamp Duty Land Tax | You | Only where the premium exceeds the threshold |
| Tribunal costs | Each side | Only if the premium cannot be agreed |
Where the leaseholders already own the freehold, or where a voluntary route is genuinely open, several of these fall away. Our packaged service at extension.lease combines the valuation, negotiation and legal work into a single fixed fee, which for a single flat is usually the simplest route.
The single biggest driver of the premium is the unexpired term. These illustrations use the same flat — worth £500,000 with a long lease, ground rent £150 a year — at four different lease lengths, to show the shape of the curve rather than to give figures you can rely on.
| Unexpired term | Marriage value? | What drives the premium |
|---|---|---|
| 95 years | No | Almost entirely the loss of ground rent. The reversion is so distant it contributes little. The premium is at its lowest here. |
| 85 years | No | Still no marriage value, but the reversion begins to carry weight. Rising steadily. |
| 79 years | Yes | Marriage value applies. The step up from 81 to 79 years is far larger than the six years from 85 to 79 would suggest. |
| 65 years | Yes | Marriage value is now a substantial share of the total, and relativity becomes the most contested assumption in the negotiation. |
The lesson from the curve is simple: the cost of waiting is not linear. A lease at 82 years is in a very different position from the same lease three years later, and the money saved by acting before the threshold usually dwarfs the cost of the professional advice.
Same flat throughout: £500,000 with a long lease, ground rent £150 a year, deferment 5%, capitalisation 7%, relativity from a curve based on the Savills 2015 and Gerald Eve 2016 unenfranchiseable graphs. Illustrative only and not valuation advice.
The calculator uses the value of your flat as its starting point, which is where location does its work. The same 76-year lease on a £1.2m flat in Kensington and a £350,000 flat in Croydon produces very different premiums, because both the ground rent burden and the marriage value scale with the value of the flat.
We act across all 32 London boroughs and the surrounding South East. Our borough pages set out local experience, the landlords active in each area and the building types we most often value there.
It gives a reasonable indication of the order of magnitude where the lease is conventional and the ground rent is straightforward. It cannot account for onerous rents, development potential, intermediate leases or tenant improvements, and it applies standard valuation assumptions rather than ones selected for your building. Treat the result as a starting point, not a figure to negotiate from.
The premium depends on the value of the flat, the unexpired term and the ground rent. Below 80 years marriage value applies and the premium rises sharply. On top of the premium you pay your own valuation and legal costs, the landlord’s reasonable costs, Land Registry fees and, where the premium exceeds the threshold, Stamp Duty Land Tax.
Marriage value is the increase in value created by granting the new lease, over and above the value of the existing lease and the landlord’s interest held separately. Under the law as it currently stands it becomes payable once the unexpired term falls below 80 years and is shared equally between leaseholder and landlord.
No. It estimates the premium payable to the landlord only. Your own valuation and legal fees, the landlord’s reasonable statutory costs, Land Registry fees and any Stamp Duty Land Tax are all additional.
No. The figure proposed in a section 42 notice must be a realistic opening figure, and serving an unrealistic one can invalidate the claim. That figure should be set by an RICS Registered Valuer who has considered your lease and the comparable evidence.
It is the single most influential input, so it is worth getting right. Use recent sale prices of genuinely comparable flats nearby, assuming a long lease and no ground rent. If you are unsure, we can advise on the long lease value as part of a formal valuation.
Please complete the fields as accurately as possible in order to receive a FREE initial estimate of your lease extension premium from one of our friendly experts. We can also offer you a complete valuation, negotiation and legal representation in tandem with our associated law firm. We will provide you with a global estimate to include all of the professional costs that are payable in addition to the premium itself so you can move forward with confidence.
Alternatively, feel free to call us directly to discuss your case on:
44 (0)20 7373 7373
At extension.lease we make the lease extension process simple, stress-free, and fully managed from start to finish.
