Lease Extension Calculator

The most advanced and accurate lease extension calculator available — instant statutory premium estimates under the 1993 Act.

Solicitor designed & maintained Schedule 13, 1993 Act methodology Free instant estimate

Your Lease Details

Choose your ground rent type, then adjust the sliders — results update live.

Years remaining on lease80 yrs = marriage value threshold
yrs
mo
Ground rent (per year)
£
Property value (once extended)
£
Advanced Valuation Parameters
Deferment rateSportelli default: 5%
%
Years remaining on lease80 yrs = marriage value threshold
yrs
mo
Current ground rent (per year)
£
Property value (once extended)
£
Advanced Valuation Parameters
Standard capitalisation rate
Cap Rate: 6.0%
RPI growth rate
RPI: 2%
Rent review frequency
Frequency: 25 years
Years until next review
Next Review: 10 years
Equivalent capitalisation rate
Equivalent Rate: Calculating...
Deferment rateSportelli default: 5%
%
Years remaining on lease80 yrs = marriage value threshold
yrs
mo
Current fixed ground rent
£
Property value (once extended)
£
Advanced Valuation Parameters
Standard capitalisation rate
Cap Rate: 6.0%
Rent review frequency
Frequency: 25 years
Years until next review
Next Review: 2035
Deferment rateSportelli default: 5%
%

Estimated premium payable

Low£
Medium£
High£

Range reflects capitalisation-rate sensitivity (±1%) applied by tribunals.

Ground rent compensation£0
Reversionary interest£0
Marriage value£0
For a more advanced cost analysis — go to the advanced dashboard →

Wait vs Act Now

Drag to see what delaying your lease extension is likely to cost.

3 years
Act now
£—
Wait 3 yrs
£—
Waiting is likely to cost an extra £—

Premium vs Years Remaining

How the premium accelerates as your lease shortens. The red marker is your current position.

8-Year HPI Premium Forecast

The likely premium if you delay 1–8 years, under 3–6% annual House Price Index growth. Click a legend entry to toggle a scenario; hover for exact figures.

Lease Extension Calculator Information

Quick answer: This calculator estimates the statutory premium payable to extend a residential lease under the 1993 Act. It is designed and maintained by a specialist solicitor and follows Schedule 13 valuation methodology to closely mirror a tribunal's likely figure.

The above figures should give you a reasonably accurate guideline to the likely premium that a Leasehold Valuation Tribunal would calculate using statutory methods. This calculator has been designed, and is maintained by, Ashley Connell - a solicitor with a specialist knowledge of Lease Extensions, with a very deep understanding of valuation methodology.

How is your lease extension cost calculated?

Quick answer: The premium is calculated using Schedule 13 of the 1993 Act, combining lost ground rent, the freeholder's reversionary interest, and marriage value (payable below 80 years remaining). Current defaults are a 5% deferment rate and 6% capitalisation rate.

A complex algorithm is used to derive the estimated premium in line with the rules set out by statute, in particular Schedule 13 of the Leasehold Reform, Housing and Urban Development Act 1993. Modern case law decisions influence this algorithm, and we constantly monitor these decisions and tweak our methods accordingly. You may be interested to know that we are currently using the following variables:

Current valuation variables used by this calculator
VariableCurrent defaultBasis
Deferment rate5%Sportelli benchmark
Capitalisation rate6%Standard tribunal-accepted rate
RelativityZucconi graphZucconi v Rescigno relativity case
Premium components (Schedule 13, 1993 Act)
ComponentDescription
Ground rent compensationPresent value of ground rent the freeholder loses over the remaining term
Reversionary interestPresent value of the freeholder regaining the property at lease expiry
Marriage valueShared uplift in value created by extending, split 50/50, only applicable under 80 years

Anyone considering extending their lease should obtain a professional Lease Extension Valuation report to assist with negotiations. This report is critical for any person wanting to negotiate the premium.

How to agree on a premium

Quick answer: Leaseholders and freeholders negotiate the premium using competing valuations, so leaseholders should submit a professional valuation report. A specialist lease extension solicitor can review that report and negotiate a lower premium.

Freeholders and leaseholders negotiate a premium based on their own valuations. Leaseholders should present their own calculations to the freeholder in a professional report with the aim of negotiating a lower premium. In fact, freeholders expect leaseholders to negotiate. We strongly recommend that you appoint a professional to deal with this aspect. Appoint a solicitor specializing in lease extensions at the very outset; a good solicitor should be able to analyze your valuation report and negotiate on your behalf to achieve the lowest possible premium. See our section on choosing a solicitor.

About our lease extension calculator

Quick answer: This tool closely follows the statutory 1993 Act valuation rules to approximate your likely premium, but it is not a substitute for a professional valuation report. Results are for guidance only and should not be used directly in negotiations.

Our results reflect a close approximation of the true cost of extending your lease in accordance with the rules, common law cases, and statutory requirements of a valuation. Our calculator adheres to these rules entirely, providing extremely accurate results; however, it does not substitute the need for a professional valuation report. Online calculators are not a basis for negotiation under the statutory lease extension process. We highly recommend that you instruct a solicitor who fully understands the valuation process and is able to negotiate on your behalf.

Disclaimer: We ask our users to not rely on our results; they are provided for guidance only.