The most important threshold in leasehold property ownership is 80 years.
Once a lease falls below 80 years, extending it becomes significantly more expensive because marriage value may become payable.
Many leaseholders do not realise that delaying a lease extension by just a few months can increase the premium they pay.
This guide explains how the 80 year rule works, why marriage value matters and how tribunal decisions influence lease extension costs.
Key takeaways
- 80 years is the key threshold for lease extensions.
- Below 80 years, marriage value may increase the premium.
- Serving a Section 42 Notice before 80 years can preserve your position.
- Comparable tribunal decisions provide useful evidence when assessing whether a quote is reasonable.
Unsure whether your quote is fair?
Compare your lease extension premium against comparable First-tier Tribunal decisions.
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What is the 80 year lease rule?
The 80 year lease rule is a widely recognised threshold in leasehold valuation. When a lease drops below 80 years of unexpired term, the statutory formula used to calculate a lease extension premium typically produces a materially higher figure.
Why does the cost increase below 80 years?
Extending a lease increases the value of the property. When a lease is above 80 years, that uplift is reflected in the premium through standard valuation components. Below 80 years, the law recognises an additional element of value created by combining the freehold and leasehold interests.
The legislation entitles the freeholder to a share of that additional uplift. In practice, this means the leaseholder pays a higher premium for an extension obtained after the lease has already fallen below the 80 year threshold than they would have paid before.
The closer a lease is to 80 years when an extension is agreed, the smaller the impact tends to be. Once well below 80 years, the additional amount can become a meaningful share of the overall premium.
What is marriage value?
Marriage value is the additional value created when a short lease is extended — the difference between the combined value of the freehold and leasehold interests before and after the extension. It only applies to leases with less than 80 years remaining, and the freeholder is entitled to a 50% share.
Lease length at a glance
| Lease length | Marriage value | Typical position |
|---|---|---|
| 90+ years | No | Lowest extension cost |
| 81–90 years | No | Good time to extend |
| Below 80 years | Usually Yes | Premium often increases |
Example of the 80 year rule
How the unexpired term of the lease tends to affect extension cost in practice:
| Lease length | Typical impact |
|---|---|
| 90 years | Marriage value generally not payable |
| 82 years | Approaching the threshold — consider acting |
| 79 years | Marriage value may apply |
| 75 years | Extension cost often materially higher |
For context on the wider drivers of premium beyond unexpired term, see our lease extension cost guide.
Can I extend before my lease reaches 80 years?
For many leaseholders, extending before the lease falls below 80 years is financially advantageous. Acting early avoids exposure to marriage value and locks in the lower premium the formula produces above the threshold.
Timing matters: the valuation date is set when a Section 42 Notice is served. Serving the notice while the lease is still above 80 years preserves that position even if negotiations run for several months.
Professional advice is usually appropriate before proceeding — a solicitor experienced in leasehold enfranchisement can confirm eligibility, and a specialist surveyor can advise on timing and likely premium. See our guide to the Section 42 Notice for how the statutory process begins.
How tribunal decisions affect lease extension costs
Lease extension premiums are calculated using a statutory formula, but the inputs to that formula involve professional judgement — particularly around deferment rates, relativity, and the unimproved freehold value. Different surveyors can produce materially different figures from the same property.
First-tier Tribunal decisions show what independent panels have determined was reasonable when both sides' valuations were tested. They are the most useful evidence of what a fair premium looks like in a comparable case.
LeaseIntel benchmarks the premium a leaseholder has been quoted against comparable published tribunal decisions — matched on unexpired term (including whether the lease is above or below 80 years), property value, ground rent profile and geography.
If you have a freeholder's figure already, you can benchmark your lease extension quote against comparable tribunal cases before agreeing the premium.
Related guides
Common mistakes leaseholders make
Waiting until after 80 years
Once the lease drops below 80 years, marriage value typically becomes payable and the premium usually increases.
Relying solely on online calculators
Calculators apply generic assumptions and cannot reflect how comparable cases have actually been resolved.
Accepting the first freeholder quote
The opening figure is a starting position. Most lease extensions are negotiated before completion.
Not comparing against tribunal decisions
Independent tribunal outcomes are one of the few objective reference points for what a reasonable premium looks like.
Don't rely solely on generic calculators.
LeaseIntel compares your case against comparable tribunal decisions and valuation data.
Benchmark My QuoteNot legal or financial advice · Independent benchmarking
Frequently asked questions
Formula estimates vs. tribunal evidence
Generic lease extension calculators produce an estimate from formula assumptions. LeaseIntel benchmarks your quote against comparable First-tier Tribunal decisions — so you can see whether the figure your freeholder has proposed appears reasonable before you negotiate, accept or serve a Section 42 Notice.
Benchmark My QuoteIndependent · Not a valuation or legal advice · Tribunal outcomes, not formula estimates