Lease Extension Calculator
years months
Important Disclaimer
This calculator is for general guidance only.
This calculator will give you a general estimate of the premium for a lease extension for a flat. It is based on data available on a national level and does not take into account local factors that may impact on the premium.
It cannot give you the actual costs. In considering the likely total cost, you should also bear in mind the leaseholder’s liability for the landlord’s costs. The eventual cost of the new lease will be the premium plus both your own and the landlord’s “reasonable” professional costs.
The estimate is likely to be helpful where there is no evidence of comparable transactions. Whether another transaction is comparable for these purposes is always determined on a case by case basis.
The calculator is for INITIAL CONSIDERATION PURPOSES ONLY.
It cannot give you a definitive figure, merely an indicative value range.
The estimate produced by the calculator should not be treated as a formal or professional valuation and is not a substitute for obtaining such a professional valuation. You should not take any action in reliance on the estimate without seeking formal advice from a surveyor, property lawyer or other qualified professional first.
Introduction: Why Lease Extensions Matter
If your lease is running below 90 years, extending it can protect your property’s value, reduce costs, and make selling or remortgaging easier. Once your lease dips below 80 years, costs go up due to what’s known as “marriage value” — a legal uplift that benefits the freeholder and increases your premium.
This page offers:
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A clear explanation of lease extensions
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A simple calculator to estimate your extension cost
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Professional guidance on what to do next
What Is a Lease Extension Calculator?
This tool gives you an estimated cost of extending your lease based on key information like:
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Years remaining on your lease
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Current ground rent
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Property value if extended
It’s a starting point — not a final quote — designed to help you budget and prepare.
Note: For an accurate premium figure, we recommend consulting a professional valuer or solicitor.
Key Inputs the Calculator Uses
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Years Remaining on Lease
Determines whether marriage value applies and affects the total cost.
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Annual Ground Rent
The rent you pay the freeholder each year. Higher rent often means a higher premium.
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Estimated Property Value (With Extended Lease)
Used to calculate the benefit you gain by extending the lease.
How the Calculator Works (Brief Overview)
The estimate is based on:
Ground Rent Loss: Compensation for rent the freeholder will no longer receive.
These are estimated using industry-accepted formulas (used by Leasehold Valuation Tribunals), but results may differ in real negotiations.
How Connaught Law Helps You
Why should I choose Connaught Law for my lease extension?
Connaught Law brings extensive expertise in leasehold extensions, ensuring the best possible outcome. Our experienced solicitors guide you through every step, providing precise legal and valuation advice, negotiating premiums, and ensuring your interests are fully protected.
Can Connaught Law negotiate my lease extension premium with the landlord?
Absolutely. We specialize in negotiating lease extensions, aiming to reduce the premium payable to your landlord. Our solicitors work closely with professional surveyors, ensuring that you pay a fair market rate rather than an inflated one.
Does Connaught Law handle disputes or tribunal cases involving lease extensions?
Yes. If an agreement cannot be reached amicably, Connaught Law is fully equipped to represent you at a Leasehold Valuation Tribunal (LVT). Our solicitors have a strong track record in achieving favourable outcomes in lease extension disputes.
How long does the lease extension process take with Connaught Law?
Typically, a statutory lease extension process takes between 3 to 6 months. Connaught Law ensures that each stage moves swiftly and efficiently, minimizing delays by proactive communication and prompt action.
What costs are involved if I engage Connaught Law for lease extension?
Our pricing is transparent and competitive. While costs depend on individual circumstances, we clearly explain all potential charges upfront. Your initial consultation is always provided without any obligation, ensuring clarity from the outset.
