A buyer finds a handsome flat in a prime London mansion block. The price looks fair, the location is right, and the lease has 79 years left. Then the solicitor mentions marriage value, and the cost of extending the lease jumps by tens of thousands of pounds. At prime values, the jump can be six figures. The buyer has not done anything wrong. The lease has simply crossed a line that changes what an extension costs, and the line is drawn at 80 years.
Marriage value is the most misunderstood charge in the lease extension process, and also one of the largest. It is not a fee, not a tax, and not a penalty. It is the value created when a short lease and the freehold interest are combined, and the law says the freeholder takes half of it. This guide explains what marriage value is, why it is nothing above 80 years and suddenly substantial below it, how it is calculated, what it costs on a prime London flat, and where the law stands in November 2026, when the reform that would abolish it has been passed but is not yet in force.
This is general information for buyers, not legal or valuation advice. Every lease extension needs a specialist RICS valuer and a conveyancer who handles leasehold work, because the figures depend on the individual lease, the building, and the valuation date.
In brief: Marriage value is half of the extra value created when a short lease and the freehold are combined into a longer lease. It applies only when the unexpired term is 80 years or fewer on the date the section 42 notice is served. Above 80 years it is nil. The freeholder receives 50 per cent of the marriage value under Schedule 13 of the Leasehold Reform, Housing and Urban Development Act 1993. On a £400,000 flat, published worked examples put marriage value at roughly £10,000 at 80 years, rising to more than £40,000 at 40 years. On a £2 million prime flat at the same assumptions, that scales to roughly £50,000 at 80 years and more than £200,000 at 40 years. The Leasehold and Freehold Reform Act 2024 legislates to abolish marriage value, but that provision is not yet in force as of November 2026, so the existing formula still applies.
The Short Answer: What Marriage Value Is
Marriage value is the increase in value that appears when two separate interests in the same property are joined together. A flat with a short lease is worth less than the same flat with a long lease, and the freeholder’s interest in the building is worth something on its own. Put the two together by extending the lease, and the combined value is higher than the sum of the two separate values. That difference is the marriage value.
The law treats that difference as something the leaseholder and the freeholder share. Under Schedule 13 of the Leasehold Reform, Housing and Urban Development Act 1993, the freeholder receives 50 per cent of the marriage value as part of the premium for a statutory lease extension. The leaseholder keeps the other half, in the form of the increased value of the flat once the lease is extended.
A simple way to think about it is to imagine the flat as two pieces. The first piece is the leaseholder’s flat with its current short lease. The second piece is the freeholder’s interest, which includes the ground rent and the right to get the flat back when the lease ends. Separately, the two pieces are worth a certain amount. Together, as a long lease, they are worth more, because a buyer will pay more for a flat with 169 years left than for the same flat with 79 years left, and the freeholder no longer holds a reversion that is about to become valuable. The gap between the combined value and the sum of the separate values is the marriage value, and the freeholder takes half of it.
This is why marriage value is sometimes described as the price of marrying the lease to the freehold. The name is old, and the concept is specific to English leasehold law. It has nothing to do with marriage in the ordinary sense, and nothing to do with the value of the flat as a home. It is a valuation concept, and it only exists because the law says the freeholder must be compensated for giving up the benefit of a short lease reverting to them.
The 80-Year Line: When Marriage Value Switches On
The 80-year line is the whole story of marriage value. Above 80 years of unexpired term, marriage value is nil. At 80 years or fewer, it applies, and it grows as the lease shortens.
The test is applied on a specific date: the date the leaseholder serves the section 42 notice that starts a statutory lease extension. If the unexpired term on that date is 80 years and one day, marriage value is zero. If it is 79 years and 364 days, the freeholder is entitled to 50 per cent of the marriage value. One day makes the difference, which is why valuers and conveyancers treat the notice date as a deadline rather than a formality.
The reason for the line is relativity. Relativity is the ratio between the value of a flat with a given lease length and the value of the same flat with a very long lease or freehold. A flat with 85 years left is worth nearly as much as the same flat with 150 years left, so combining the interests creates almost no extra value and the marriage value is nil. A flat with 50 years left is worth much less than the same flat with a long lease, so the combination creates a large uplift and the marriage value is substantial. The 80-year line is where the law draws the boundary between those two situations.
Published relativity figures make the pattern concrete. The Gerald Eve 2016 relativity table, which valuers commonly use, puts a flat with 72 years remaining at roughly 86 per cent of its long-lease value, and a flat with 50 years remaining at roughly 70.5 per cent. The shorter the lease, the wider the gap between the short-lease value and the long-lease value, and the wider the gap, the larger the marriage value. At 80 years the gap is small enough that the law treats it as nothing. At 60 years it is material. At 40 years it is very large.
For a buyer, the practical point is simple. A lease with 82 years left and a lease with 78 years left may look almost identical on a property listing, and they may be priced almost identically. The cost of extending them is not almost identical. The 82-year lease can be extended without marriage value. The 78-year lease cannot, and the premium will be higher by the freeholder’s half of the marriage value. That difference should be in the buyer’s mind before the offer is made, not discovered after exchange.
The Three Parts of a Lease Extension Premium
A statutory lease extension premium is made up of three parts. Marriage value is the third part, and it is the part that surprises buyers, because the first two parts are relatively predictable and the third is not.
The first part is the capitalised ground rent. The freeholder gives up the right to receive ground rent for the rest of the current lease, so the premium includes the present value of that income stream. Ground rent on a prime London flat is often modest, particularly on older leases where the rent was fixed decades ago, so this part of the premium is usually the smallest. Where ground rent doubles at intervals, or where it was set at a meaningful figure on a newer lease, this part is larger. The calculation uses a capitalisation rate, and published worked examples commonly use 6 per cent.
The second part is the freeholder’s reversion. The freeholder gives up the right to get the flat back when the lease expires, so the premium includes the present value of that future reversion. The calculation discounts the value of the flat at the end of the lease back to today, using a deferment rate. The established rate from the case of Cadogan v Sportelli (2007) is 5.0 per cent for flats and 4.75 per cent for houses. Because the reversion is far in the future on a lease with 80 years left, its present value is small. On a lease with 40 years left, the reversion is much closer and its present value is much larger.
The third part is the marriage value, where it applies. It is 50 per cent of the difference between the combined value of the extended lease plus the freeholder’s interest after the extension, and the sum of the current lease value, the capitalised ground rent, and the freeholder’s current reversion. In plain terms, it is half of the uplift created by the extension itself.
The formula, as valuers apply it, is:
Premium = capitalised ground rent + freeholder’s reversion + 50 per cent of marriage value (if the unexpired term is 80 years or fewer).
The full cost breakdown, with worked premiums at £1 million, £2 million and £3 million, is set out in the guide to lease extension cost on a prime London flat. This article explains the marriage value element in depth rather than repeating the whole calculation.
Two features of the formula matter for buyers. First, the premium is not a round number and it is not negotiable in the ordinary sense. It is a valuation, and the two sides’ valuers can disagree about the inputs, particularly relativity and the value of the extended lease. That disagreement is resolved by negotiation or, if it cannot be agreed, by the First-tier Tribunal. Second, the premium is not the whole cost of extending. Legal fees, valuation fees and the freeholder’s reasonable costs are additional, and stamp duty can apply where the premium exceeds £125,000, which it almost always does at prime values.
Worked Illustration: What Marriage Value Costs at Prime Values
The figures below are an illustration, not a valuation. They are scaled from a published worked example for a £400,000 flat, where marriage value is roughly £10,000 at 80 years and more than £40,000 at 40 years, and they use the same relativity assumptions. A real premium depends on the individual lease, the ground rent, the building, the location, and the valuation date, and only a valuer instructed on the actual flat can give a figure to rely on. The illustration is included because it shows the scale of the problem at prime values, which is where the published examples, all worked at £250,000 to £500,000, stop being useful.
| Flat value (long lease) | Marriage value at 80 years | Marriage value at 60 years | Marriage value at 40 years |
|---|---|---|---|
| £400,000 | About £10,000 | About £25,000 | More than £40,000 |
| £1,000,000 | About £25,000 | About £60,000 | More than £100,000 |
| £2,000,000 | About £50,000 | About £125,000 | More than £200,000 |
| £3,000,000 | About £75,000 | About £190,000 | More than £300,000 |
Three things stand out from the table. First, the marriage value is a small fraction of the flat’s value at 80 years, roughly 2.5 per cent, and it grows quickly as the lease shortens. Second, at prime values the absolute numbers are large even though the percentages are modest. A £50,000 marriage value on a £2 million flat at 80 years is a real sum, and it is only the freeholder’s half that is shown here, because the table shows the full marriage value and the premium includes 50 per cent of it. Third, the cost of waiting is visible in the columns. A lease that falls from 80 years to 60 years does not just lose value. It also becomes substantially more expensive to extend, because the marriage value grows while the flat’s value falls.
That last point is the one that matters most in practice. A buyer who purchases a flat with 79 years left and extends immediately pays marriage value on a 79-year lease. A buyer who waits five years pays marriage value on a 74-year lease, on a flat that is worth less than it was. Delay costs money twice over, and it is the reason every guide to lease extension says the same thing: extend early, and never let a lease drift below 80 years without a plan.
The table also explains why marriage value is a prime-market problem rather than a general one. On a £250,000 flat outside London, the marriage value at 80 years is a few thousand pounds, and it is a minor part of the transaction. On a £2 million flat in Kensington, it is £50,000 at 80 years and six figures at 40 years, and it can change whether the purchase makes sense at all. That is why the original lease extension guide worked the numbers at prime values, and why buyers of prime leasehold flats need to understand this charge before they buy rather than after.
Relativity: Why the Number Grows as the Lease Shortens
Relativity is the engine inside marriage value, and it is worth understanding because it explains why the charge grows so fast as the lease shortens.
Relativity is the value of a flat with a given lease length expressed as a percentage of the value of the same flat with a very long lease. A flat with 95 years left might have a relativity of 95 per cent or more. A flat with 80 years left is around 90 per cent. A flat with 60 years left is around 80 per cent. A flat with 40 years left is around 65 per cent. The exact figures depend on which relativity graph the valuer uses, and valuers disagree about the graphs, which is one of the main sources of dispute in lease extension negotiations.
The Gerald Eve 2016 graph is the one most commonly cited. It puts relativity at roughly 86 per cent at 72 years and roughly 70.5 per cent at 50 years. Other graphs give slightly different figures, and the difference between graphs can move a premium by thousands of pounds on an ordinary flat and by tens of thousands on a prime flat. The Upper Tribunal has considered relativity graphs in detail, and the choice of graph remains a matter for the valuers in each case rather than a settled rule.
The consequence for the buyer is that the marriage value is not a fixed percentage of the flat’s value. It depends on where the lease sits on the relativity curve, and the curve steepens as the lease shortens. The fall from 90 per cent relativity at 80 years to 86 per cent at 72 years is four points over eight years. The fall from 70.5 per cent at 50 years to roughly 65 per cent at 40 years is five and a half points over ten years, but it is five and a half points on a much larger gap, and the marriage value grows accordingly. This is why a lease with 45 years left is not simply a little worse than a lease with 55 years left. It is materially worse, and materially more expensive to extend.
Relativity also explains why two flats in the same building can have very different extension costs. A flat with 83 years left has no marriage value at all. A flat with 77 years left in the same block, on the same staircase, has a marriage value that adds thousands to its premium. The flats are otherwise identical. The difference is entirely in the lease length, and it is entirely in the relativity figure.
The Notice-Date Trap: Serve Before You Cross 80 Years
The valuation date for a statutory lease extension is the date the section 42 notice is served, and the unexpired term is measured on that date. That single rule creates a trap that catches buyers every year.
A leaseholder who serves the notice with 80 years and one day remaining pays no marriage value. A leaseholder who serves the same notice a week later, with 79 years and 358 days remaining, pays marriage value in full. The premium can jump by tens of thousands of pounds because of a delay of days, and at prime values the jump can be six figures.
The trap has three common forms. The first is the buyer who completes a purchase with 81 years left and assumes there is time. There is time, but not much, and the extension process itself takes months. The notice must be served, the freeholder has two months to respond with a counter-notice, the valuers negotiate, and the terms must be agreed or referred to the Tribunal. A lease that starts at 81 years can easily cross 80 years while the paperwork is being prepared, if nobody is watching the calendar.
The second is the owner who waits for the reform. The Leasehold and Freehold Reform Act 2024 legislates to abolish marriage value, and many owners have decided to wait for abolition rather than pay a premium that includes it. That is understandable, and it is also a gamble, because the abolition provision is not yet in force and no commencement date has been confirmed. Every year of waiting is a year off the lease, and a year off the lease increases the marriage value that will be payable if the owner eventually extends under the existing law. Waiting is only free if the reform arrives before the lease falls much further.
The third is the overseas owner who is not in London to manage the process. A lease extension can be handled remotely, and the original guide explains how, but it still needs a valuer instructed, a solicitor instructed, and a notice served on a specific date. An owner who is abroad and inattentive to the lease can lose the 80-year boundary without noticing, and discover the cost only when a valuation is finally obtained.
The practical rule is simple. Know the exact unexpired term, know the date it crosses 80 years, and serve the section 42 notice before that date if an extension is planned. The notice date is the valuation date, and the valuation date decides whether marriage value is nil or substantial. Nothing else in the process has the same leverage over the final premium.
Reform: The 2024 Act, Abolition, and What Is Actually in Force
The reform position is the part of this article most likely to be out of date the fastest, so it is dated precisely: this section describes the position as of November 2026, and any buyer acting on it should check the current position with their solicitor.
The Leasehold and Freehold Reform Act 2024 legislates to abolish marriage value and to set a standard 990-year term for lease extensions. Those are the headline provisions, and they are the reason many owners are waiting. But the valuation provisions of the Act, including the abolition of marriage value, are not yet in force. Until they are commenced, the existing formula still applies, and premiums are still calculated with marriage value included where the unexpired term is 80 years or fewer.
The government ran a consultation on valuation rates, which closed on 21 October 2026 after opening on 15 July 2026. Freeholders have appealed against a High Court ruling from October 2025, and that appeal is ongoing. No commencement date for the marriage value abolition has been confirmed. That is the position as of November 2026, and it may change, but it has not changed yet.
One reform provision is already in force. The two-year ownership requirement for a statutory lease extension was abolished on 31 January 2025 under section 27 of the 2024 Act. A buyer can now serve a section 42 notice immediately after completing a purchase, without waiting two years. That change matters for the notice-date trap described above, because it removes the old reason to delay. A buyer who completes with 81 years left can serve the notice at once, rather than waiting and watching the lease cross 80 years in the meantime.
The honest summary for a buyer in November 2026 is this. Marriage value may be abolished in the future, and the legislation to abolish it exists. It has not been brought into force, no date has been set, and the existing law applies to every extension completed today. A buyer who assumes abolition has happened will under-budget the premium. A buyer who waits for abolition is betting that it arrives before the lease shortens enough to cost more than the saving. Both positions should be taken with advice, not assumed.
Marriage Value for Overseas Owners of Prime Flats
Marriage value hits overseas owners of prime London flats harder than almost anyone else, for reasons that have nothing to do with the law and everything to do with how these flats are bought and held.
The first reason is value. Prime London flats are the most expensive leasehold flats in the country, and marriage value scales with value. A 50 per cent share of the marriage value on a £3 million flat is a sum that would buy a flat outright in much of the country. Overseas buyers, who are the main purchasers of prime leasehold flats, are therefore the main payers of large marriage values.
The second reason is the freeholder. Much of prime central London sits on the great estates, and the freeholder of a prime flat is often an estate landlord with professional advisers and a long-term interest in the building. These freeholders are experienced in lease extension negotiations, and their valuers know the relativity arguments well. An overseas buyer extending a lease in a mansion block on an estate is negotiating with a counterparty that does this every week. Good advice on the buyer’s side is not optional.
The third reason is distance. An overseas owner may visit London only a few times a year, and the lease length is easy to overlook between visits. Service charges, which arrive as an annual demand, are hard to miss. Ground rent, which is often modest, is easy to pay and forget. The lease length, which silently shortens by a year every year, is the easiest of all to ignore, until a valuation reveals that it has crossed 80 years and the premium has jumped. The running costs of a prime London home, including service charges and the annual demands that come with them, are set out in the guide to the annual running costs of a luxury London home, and the lease length deserves the same annual attention as any of those bills.
The fourth reason is the purchase itself. Overseas buyers often buy leasehold flats through a company, or buy a flat that is already short, because the price reflects the lease length and the purchase looks like good value. It can be good value, provided the extension cost is understood before the purchase. A flat priced £100,000 below its long-lease value with 75 years left is not a bargain if the extension premium, including marriage value, is £120,000. The discount and the premium must be compared, and the comparison must include marriage value, not just the capitalised ground rent and the reversion.
For an overseas buyer, the checklist before buying a leasehold flat in prime London is therefore short and specific. Know the exact unexpired term. Know whether it is above or below 80 years. Know the estimated extension premium, including marriage value, from a valuer instructed before exchange. Know the date the lease crosses 80 years, if it has not already. And know that the two-year ownership rule no longer applies, so an extension can be started immediately after completion. The guide to the total cost of buying a luxury property in the UK sets out the full purchase cost stack, and the extension premium belongs in that calculation for any flat with a lease under 90 years.
What Marriage Value Is Not
Marriage value is widely misunderstood, and three confusions cause most of the trouble.
It is not a fee charged by the freeholder. A fee is a charge for a service, and it is usually fixed or based on time spent. Marriage value is a share of an increase in value, calculated by a valuer, and it varies with the lease length, the flat’s value, and the relativity figure. It is not something the freeholder invents or sets. It is something the statute provides for, and the valuer calculates.
It is not ground rent, and it is not a service charge. Ground rent is the annual rent payable under the lease. Service charges are the annual cost of running the building, and they are explained in the guide to service charges on luxury London flats. Marriage value is a one-off capital sum payable as part of the extension premium. It is not recurring, it is not an annual demand, and it does not pay for anything in the building. Confusing it with either of the annual charges understates the extension cost, because the buyer budgets for the annual charges and forgets the capital sum.
It is not a tax. No part of the marriage value goes to the government, and it is not collected by HMRC. Stamp duty can apply to the extension premium, including the marriage value element, where the premium exceeds £125,000, and that is a separate calculation. The guide to stamp duty for overseas buyers explains the surcharges that apply to overseas purchasers, and the premium itself, including marriage value, is the figure on which any stamp duty on the extension is assessed.
Frequently Asked Questions
What is marriage value in a lease extension?
Marriage value is 50 per cent of the extra value created when a short lease and the freehold interest are combined into a longer lease. It is payable to the freeholder as part of the premium for a statutory lease extension, under Schedule 13 of the Leasehold Reform, Housing and Urban Development Act 1993. It applies only when the unexpired term is 80 years or fewer on the date the section 42 notice is served.
At what lease length does marriage value apply?
At 80 years or fewer. Above 80 years of unexpired term on the notice date, marriage value is nil. At 80 years or fewer, it applies and grows as the lease shortens. The test is applied on the date the section 42 notice is served, so a lease with 80 years and one day left on that date has no marriage value, and a lease with 79 years and 364 days has marriage value in full.
How is marriage value calculated?
It is the difference between the combined value of the extended lease plus the freeholder’s interest after the extension, and the sum of the current lease value, the capitalised ground rent, and the freeholder’s current reversion. The freeholder receives 50 per cent of that difference. The calculation uses a deferment rate of 5.0 per cent for flats, from Cadogan v Sportelli (2007), and a relativity figure for the current lease length, commonly from the Gerald Eve 2016 table.
How much is marriage value on a £2 million flat?
It depends on the lease length. On the published worked example for a £400,000 flat, marriage value is roughly £10,000 at 80 years and more than £40,000 at 40 years. Scaled to a £2 million flat at the same assumptions, that is roughly £50,000 at 80 years and more than £200,000 at 40 years. These are illustrations, not valuations. A real figure needs a valuer instructed on the actual flat.
Has marriage value been abolished?
Not yet. The Leasehold and Freehold Reform Act 2024 legislates to abolish marriage value, but that provision is not yet in force as of November 2026, and no commencement date has been confirmed. The valuation-rates consultation ran from 15 July to 21 October 2026, and freeholders’ appeal against the October 2025 High Court ruling is ongoing. Until commencement, the existing formula still applies.
Can I extend my lease without paying marriage value?
Yes, if the unexpired term is above 80 years on the date the section 42 notice is served. Marriage value is nil above 80 years. If the lease is already below 80 years, marriage value is payable on a statutory extension. An informal extension negotiated directly with the freeholder may be agreed on different terms, but the freeholder is not obliged to agree, and an informal deal can carry its own disadvantages, including a new ground rent.
Does marriage value apply to houses as well as flats?
Yes, where the house is leasehold and the extension is under the 1993 Act. The deferment rate for houses is 4.75 per cent rather than 5.0 per cent for flats. Marriage value on a leasehold house is calculated on the same principle, but leasehold houses are far less common in prime London than leasehold flats, and the figures in this guide are worked for flats.
Should I wait for reform before extending?
That is a decision to take with a valuer and a solicitor, not on the basis of this guide. Waiting saves the marriage value only if abolition is commenced before the extension is completed. Every year of waiting shortens the lease, which increases the marriage value that would be payable under the existing law, and reduces the value of the flat. The two-year ownership requirement was abolished on 31 January 2025, so an extension can now be started immediately after purchase.