HouseCheckup's lease extension calculator estimates the premium you would pay to extend your lease under the Leasehold Reform, Housing and Urban Development Act 1993. Around 4.5 million homes in England are leasehold according to the Ministry of Housing, and lease length directly affects property value — a lease below 80 years triggers 'marriage value', significantly increasing the cost of extension. Enter your lease details to see an estimated premium before instructing a surveyor.
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The cost depends on the property value, remaining lease length, and ground rent. A flat worth £300,000 with 80 years remaining might cost £10,000–£15,000 to extend. Below 80 years, marriage value adds 50% of the gain in value, making it significantly more expensive. HouseCheckup estimates the statutory premium plus typical professional fees.
When a lease drops below 80 years, the statutory extension formula includes 'marriage value' — the increase in property value created by extending the lease. You must pay the freeholder 50% of this marriage value on top of the standard premium. This can add thousands of pounds. Extending before reaching 80 years is almost always cheaper.
You must have owned the property for at least two years. The process involves: getting a professional valuation (£500–£1,000), serving a Section 42 notice on the freeholder, negotiation or tribunal determination, and completion. The whole process typically takes 6–12 months and costs £3,000–£5,000 in professional fees on top of the premium.
The Leasehold and Freehold Reform Act 2024 aims to make lease extensions cheaper by removing marriage value and capping ground rents. Once fully enacted, extending a lease should be simpler and more affordable. HouseCheckup will update the calculator when the new rules come into force.