What is marriage value?
Marriage value is one of those leasehold terms that sounds complicated but boils down to a simple idea. When you extend a short lease, the flat becomes worth more. The "marriage" is the merging of your existing short lease with the new extension to create a single, more valuable long lease. The increase in value that this merger creates is the marriage value.
Under the Leasehold Reform, Housing and Urban Development Act 1993, if your lease has fewer than 80 years remaining, you must pay the freeholder 50% of this increase as part of the lease extension premium. Above 80 years, you pay nothing for marriage value. Below it, you pay half the uplift.
This is not a minor technicality. For many London flat owners, marriage value is the single largest component of the extension cost. It can add tens of thousands of pounds to the price of extending, and it is the main reason why leases below 80 years are so much more expensive to deal with than those above.
How marriage value is calculated
The calculation follows a specific formula set out in Schedule 13 of the 1993 Act. In simplified terms, it works like this:
- Determine the value of the flat with the existing short lease (this is based on relativity tables - see our guide on how a short lease affects value)
- Determine the value of the flat with the extended lease (typically very close to its freehold value)
- Determine the value of the freeholder's interest before and after the extension
- Calculate the total gain from the extension (the marriage value)
- The leaseholder pays 50% of that gain to the freeholder
The full statutory calculation also includes the capitalised value of future ground rent payments and the present value of the freeholder's reversion (their right to get the property back when the lease expires). Marriage value sits on top of those elements.
Worked example - a flat at 65 years
Let us use a real-world scenario. You own a two-bedroom flat in Wandsworth. With a long lease, it would be worth £400,000. Your lease currently has 65 years remaining.
Using standard relativity tables, a flat at 65 years typically retains about 77% of its long-lease value. So the flat's current value is approximately £308,000.
After extending the lease by 90 years (to 155 years at a peppercorn ground rent), the flat would be worth its full long-lease value: £400,000.
The marriage value is the difference:
- Value after extension: £400,000
- Value before extension: £308,000
- Plus the reduction in the freeholder's interest (say £15,000 for this example)
- Total marriage value: approximately £77,000
- Your share (50%): approximately £38,500
So the marriage value component alone is £38,500. On top of that, you would pay the capitalised ground rent and the diminution in the freeholder's reversion, bringing the total premium to perhaps £45,000-£55,000 depending on the ground rent terms.
Worked example - a flat at 55 years
Now take the same flat, but with only 55 years remaining. At 55 years, relativity drops to around 67%, giving a current value of roughly £268,000.
- Value after extension: £400,000
- Value before extension: £268,000
- Plus reduction in freeholder's interest (say £20,000)
- Total marriage value: approximately £112,000
- Your share (50%): approximately £56,000
Just 10 years' difference on the lease, but the marriage value component has jumped from £38,500 to £56,000. The total extension premium could be £65,000-£80,000. This is why surveyors and solicitors who specialise in lease extensions stress the importance of acting early.
The 80-year cliff edge
The 80-year threshold creates what is effectively a cliff edge in the pricing of lease extensions. Here is what that looks like in practice for the same 400,000-pound flat:
- At 82 years - no marriage value. Total premium might be £10,000-£15,000 (capitalised ground rent plus diminution in freeholder's reversion only).
- At 79 years - marriage value kicks in. Total premium might be £22,000-£30,000.
- At 75 years - total premium might be £28,000-£38,000.
- At 70 years - total premium might be £35,000-£50,000.
The jump from 82 years to 79 years - just three years' difference - could roughly double your extension cost. This is the single most important thing to understand about marriage value. If your lease is anywhere near 80 years, every year of delay is directly costing you money.
Which relativity table matters?
The marriage value calculation depends heavily on the relativity rate used - the percentage of freehold value that a short-lease flat is deemed to be worth. There are several competing relativity graphs used in practice:
- Savills enfranchiseable - widely used and often cited in tribunal decisions
- Gerald Eve 2016 - tends to produce higher relativity (meaning lower marriage value for the leaseholder, which is favourable)
- RICS 2009 graphs of relativity - another commonly referenced set
The choice of graph can make a difference of several thousand pounds to the premium. Your surveyor's job is to argue for the relativity rate most favourable to you, while the freeholder's surveyor will push for a lower relativity (which increases the marriage value and therefore the premium). This is one of the reasons lease extension negotiations can drag on and sometimes end up at the First-tier Tribunal (Property Chamber).
The Leasehold and Freehold Reform Act 2024 proposes to replace this system with a standardised calculation, but until the secondary legislation is in place, the current negotiation-based approach applies.
Will marriage value be abolished?
Yes - eventually. The Leasehold and Freehold Reform Act 2024 includes a provision to abolish marriage value entirely. When implemented, this would mean that extending a lease below 80 years would cost broadly the same (proportionally) as extending one above 80 years. The cliff edge would disappear.
For the flat in our example above, this could mean the difference between paying £55,000 (with marriage value at 65 years) and perhaps £15,000-£20,000 (without it). The savings would be substantial.
However, this provision is not yet in force. As of April 2026, the secondary legislation needed to implement the new valuation method has not been finalised. Marriage value abolition is expected late 2026 at the earliest, but the Government has not committed to a specific date. For a fuller picture of where things stand, read our guide to the 2024 Act.
Until the change takes effect, the current rules apply in full. If your lease is sitting at 82 or 83 years, we would strongly encourage you to extend now rather than gamble on the reforms arriving before your lease crosses the 80-year line.
How marriage value affects your sale price
If you are selling a flat with a lease under 80 years, marriage value affects you even if you never extend the lease yourself. Here is why: any buyer looking at your flat will calculate what it would cost them to extend after purchase. That calculation includes marriage value. They will then subtract that cost from what they are willing to pay.
In effect, you bear the cost of marriage value whether you extend or not. If you extend before selling, you pay it directly. If you sell without extending, the buyer deducts it from their offer.
On the open market, this creates a double problem. The flat's value is depressed by the short lease, and on top of that, buyers factor in the cost and hassle of a 6-12 month extension process. Many open-market buyers will simply walk away rather than take on the complexity.
When we buy a short-lease flat, we take on the marriage value cost and the extension process ourselves. Our offer accounts for this, but it means you avoid the expense, the delay, and the risk of the extension process. You get a clean cash sale, typically completing in 2-4 weeks.
Get a free valuation to see what your flat is worth today, or use our lease extension calculator to estimate the cost of extending under the current rules.