Resources

Lease extension calculator

Use this free tool to estimate the statutory premium for extending your lease in England and Wales, based on years remaining, property value, and ground rent. It is designed for flat leaseholders planning ahead — not as a substitute for a formal valuation.

Taking control through Right to Manage does not change your lease length, but once your building runs through an RTM company you can often organise lease extensions together: sharing surveyor and legal costs and keeping decisions transparent — much like self-managed blocks coordinate maintenance with modern tools instead of relying on a distant landlord or agent.

For context on titles and options, read leasehold vs freehold explained.

Years remaining on lease

Between 1 and 250 years.

Property value (£)

Ground rent (£ per year)

Use 0 if your lease is at a peppercorn rent.

Estimated premium

£349,189

How this estimate breaks down

Diminution in reversion value£347,205
Loss of ground rent£1,984
Marriage value (50% share where applicable)£0

Disclaimer: This calculator provides an estimate only. Lease extension premiums are subject to negotiation and tribunal determination. You should seek advice from a qualified surveyor before proceeding.

Thinking about Right to Manage instead? Check if your building qualifies

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New to lease concepts? See leasehold vs freehold explained or browse the full resources hub.

Frequently asked questions

Short answers for orientation — not tailored to your lease or building.

How accurate is this calculator?

This calculator uses the standard statutory formula and a 5% deferment rate following the Sportelli case. It gives a reliable estimate but the actual premium is subject to negotiation and professional valuation. Use it as a starting point, not a final figure.

What is marriage value?

Marriage value is an additional component that applies when a lease has fewer than 80 years remaining. It represents the increase in the property value that results from extending the lease, and leaseholders must share 50% of this uplift with the freeholder. This is why costs rise sharply below 80 years.

Should I extend my lease or do Right to Manage first?

They are not mutually exclusive. RTM gives you control over building management — it does not directly affect your lease length. However, once you have an RTM company, leaseholders can coordinate lease extensions collectively which can reduce professional costs. Some groups do RTM first, then address lease extensions together — see what is the Right to Manage?.

What is the deferment rate?

The deferment rate is used to calculate the present value of the freeholder's right to receive the property back at the end of the lease. Following the Sportelli case, 5% is the standard rate used by most valuers and tribunals in England and Wales.

Prefer to explore RTM first? See whether your building qualifies.

Check eligibility