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Leasehold Extension Calculator

Estimate the cost of extending your leasehold and the impact on property value.

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Estimated Premium

£70,000

New lease: 165 years

Marriage Value

£17,500

Capitalised Rent

£8,750

Solicitor

£2,000

Valuation

£750

Total Cost

£72,750

Value Uplift

£65,625

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Understanding Your Leasehold Extension

Extending a short lease is one of the most important financial decisions a leaseholder can make. A short lease reduces property value and can make it unmortgageable, especially once it drops below the crucial 80-year mark. This calculator provides a reliable estimate of the premium you might pay, but it's essential to consult a qualified surveyor for a formal valuation before starting the process. At Calculator Site, we provide the tools to help you plan these significant financial steps.

The 80-Year Threshold is Critical

Once a lease drops below 80 years, 'marriage value' applies. This is a legal concept where the freeholder is entitled to 50% of the value unlocked by the extension, significantly increasing the cost. Mortgage lenders are also often unwilling to lend on properties with leases under 80 years, making it difficult to sell or remortgage. It's always cheaper to extend before you hit this point. You might find our Mortgage Calculator useful for exploring financing options.

Key Factors in Extension Costs

The premium for a lease extension is not a fixed price. It's calculated based on several key factors, including your property's value, the remaining lease term, and your annual ground rent. The formula aims to compensate the freeholder for the loss of ground rent income and their interest in the property. Our Mortgage Overpayment Calculator can help you assess affordability.

+90 Years

Added to lease via statutory route

<80 Years

Triggers expensive 'marriage value'

£0

Future ground rent after extension

How to use this Calculator Site tool

Enter your property's current estimated market value, the number of years left on your lease, and the annual ground rent you currently pay. The calculator will provide an instant estimate of the premium and other associated costs. Adjust the numbers to see how the costs change – for example, see how much the premium increases as the lease gets shorter. For official leasehold guidance, visit GOV.UK leasehold guide.

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