The 80-year threshold is the most important milestone for any UK leaseholder. Learn how marriage value works and why crossing it costs thousands.
What Is the 80-Year Rule?
Of all the numbers on a lease, 80 is the one that matters most. Once a lease has 80 years or fewer left on the day a lease extension notice is served, a cost called marriage value is added to the premium, and it can double the price. This guide explains why the line exists, what it costs, how to stay on the right side of it and what the rule means for mortgages and resale.
What Is the 80-Year Rule?
When you extend a lease under the 1993 Act, the premium has three parts: capitalised ground rent, the freeholder’s reversion and, where the unexpired term is 80 years or fewer, marriage value (see how the premium is calculated). Marriage value is 50% of the increase in the combined value of the lease and freehold interests created by the extension (see marriage value explained). Above 80 years the law says it is disregarded and is not payable.
The line is sharp. On our calculator a £400,000 flat with £200 ground rent costs about £11,500 to extend at 81 years but about £21,900 at 80 years, because about £10,100 of marriage value switches on.
What It Costs: Same Flat, Different Lease Lengths
For a £350,000 flat with £200 ground rent, our calculator (5% rates, Gerald Eve 2016 relativity) gives:
| Years left | Marriage value | Total premium |
|---|---|---|
| 85 | £0 | about £9,400 |
| 81 | £0 | about £10,600 |
| 80 | about £8,600 | about £19,400 |
| 79 | about £9,300 | about £20,500 |
| 70 | about £16,100 | about £31,400 |
| 60 | about £24,300 | about £46,600 |
Two effects are at work. At 80 years marriage value switches on all at once, so the premium roughly doubles. Below 80 each year of shortening then adds to both the reversion and the marriage value, so the cost keeps climbing, by about £1,000 a year for a flat of this value just below the line. Figures scale with property value and are estimates, not valuations; a surveyor’s figure may differ.
Real Cost of Waiting One Year Below 80
Property: £300,000 | Ground rent: £250/yr
At 79 years: premium approximately £18,400
At 78 years: premium approximately £19,300
Cost of waiting one year: approximately £940 extra — plus your lease is a year shorter and harder to mortgage.
The Timing Rule That Saves Money
The lease length used to value the premium is the unexpired term on the date the section 42 notice is served, not the date the extension completes. So if you serve the notice while the lease has more than 80 years left, marriage value is not payable even if the process takes six or twelve months and the lease ticks below 80 before completion. What matters is serving in time, which is why advice is to start well before the line (many advisers suggest at around 82–85 years, to allow for taking advice and getting a valuation). The notice must be valid, so it needs specialist input; see our section 42 guide.
The reverse matters too: if you are buying a flat with 80–82 years left, you can now serve the notice straight away, because the two-year ownership rule was removed on 31 January 2025. A buyer should factor the cost of extending into the price they offer.
Mortgages and Resale
Lenders set their own minimum remaining term, and policies vary. Many become cautious as a lease approaches 80 years and some refuse short leases, often looking at the term remaining at application or at the end of the mortgage. A flat that cannot be mortgaged is hard to sell, so the 80-year line also affects buyers’ willingness to pay. In practice, buyers and their solicitors will ask who pays for the extension, and a short lease is often priced down by more than the cost of the extension itself.
Should I Wait for the 2024 Act to Abolish Marriage Value?
The Leasehold and Freehold Reform Act 2024 provides for marriage value to be abolished, but the provision is not in force and no commencement date is confirmed; a freeholder challenge is still before the Court of Appeal. If your lease is already well below 80, waiting risks paying more in reversion each year with no certainty that reform arrives. If you are close to 80, serving before you cross the line secures today’s position. See the 2024 Act and Should I wait or extend now?
What to Do Right Now
- Check your lease length on the title or in your lease and work out the date it will reach 80 years.
- If you are within about five years of 80, take specialist advice now.
- Use our free calculator to compare the cost today with the cost after crossing the line.
- Instruct a specialist leasehold solicitor and a RICS valuer before you serve notice (see fees).
Frequently Asked Questions
Where a lease has 80 years or fewer left on the date a lease extension notice is served, marriage value is payable as part of the premium. Above 80 years it is not. Marriage value is 50% of the uplift in combined value created by the extension and can roughly double the premium.
It depends on the property value and lease length. For a £350,000 flat with £200 ground rent our calculator gives about £10,600 at 81 years but about £19,400 at 80 years, and about £31,400 at 70 years. The extra is marriage value plus a larger reversion, so a surveyor's figure may differ.
At the date the section 42 notice is served. If the lease has more than 80 years left on that date, marriage value is not payable even if the lease falls below 80 before the extension completes.
Yes. You keep your statutory right to extend at any lease length, but marriage value is added to the premium and the cost rises each year. The two-year ownership rule was removed on 31 January 2025, so you can claim immediately after buying.
The Act provides for marriage value to be abolished, but the provision is not in force and there is no confirmed commencement date. Until it is commenced, marriage value is payable below the 80-year line. Do not delay on the assumption that it will arrive in time.
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Primary Sources & Statutory References
This guide is researched from official and primary sources. Check them directly before relying on any figure or date.
- Leasehold Reform, Housing and Urban Development Act 1993
- Leasehold and Freehold Reform Act 2024
- LEASE – the Leasehold Advisory Service
- GOV.UK: Leasehold property
- Valuation basis: Earl Cadogan v Sportelli [2007] EWCA Civ 1042 (5% deferment rate for flats).
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This article is for general information only and does not constitute legal or financial advice. Always consult a specialist solicitor and RICS surveyor before taking any action.