What is marriage value in a lease extension?

Marriage value arises when a lease has fewer than 80 years remaining. It is the increase in the flat's value created by extending the lease, the freeholder is entitled to 50% of this gain. Marriage value can significantly increase the premium. For a flat worth £300,000 with 72 years remaining, the marriage value element alone could add £15,000–£30,000 to the premium.

What is the 80-year lease extension threshold?

Below 80 years, the freeholder becomes entitled to 50% of the marriage value, which can substantially increase the cost. This is why leaseholders are strongly advised to extend before falling below 80 years. Mortgage lenders often require at least 70–85 years remaining to lend on a leasehold property.

What is a statutory lease extension?

Under the Leasehold Reform, Housing and Urban Development Act 1993, qualifying leaseholders have the right to a statutory lease extension of 90 years (added to the unexpired term) at a peppercorn (zero) ground rent. To qualify, you must have owned the flat for at least 2 years. The Leasehold and Freehold Reform Act 2024 makes further changes, check the current position with a solicitor.

Can I negotiate a lease extension directly with my freeholder?

Yes, an informal (non-statutory) lease extension can be negotiated directly with the freeholder at any time. This can be quicker and cheaper in some cases, but you lose the statutory protections including the peppercorn ground rent. The statutory route provides more certainty but typically takes 6–12 months.

Do I need a solicitor to extend my lease?

You need a specialist leasehold solicitor and a leasehold valuation surveyor (RICS) to assess the premium. The freeholder's reasonable professional costs are also recoverable from you. Professional costs on top of the premium typically total £3,000–£6,000. Always instruct specialists for a lease extension.

Updated 1 May 2026

Lease Extension Calculator · Free UK Premium Estimate 2026

Q: How much does it cost to extend a lease?

The premium (the price you pay the freeholder) for a statutory lease extension is calculated using the Dearing formula, which considers: the ground rent and term remaining; the reversion value to the freeholder; and marriage value if there are fewer than 80 years left. Typical premiums range from a few thousand pounds (long lease, low ground rent) to tens of thousands (short lease, high property value).

Estimate the premium for extending your leasehold, including the critical 80-year marriage value threshold. No personal details required.

✓ Free to use✓ Marriage value alert✓ 80-year threshold✓ Instant estimate

Lease Extension Calculator

Enter flat value, years remaining, and ground rent, premium estimate appears instantly

Flat value (£)

Years remaining on lease

Annual ground rent (£)

Warning: Your lease is under 80 years, marriage value applies, significantly increasing the premium. Consider extending before it falls further.

Estimated premium range

£14,945.83 – £24,979.17

Includes ~£2,250.00 marriage value (50% of gain)

Flat value

£300,000.00

Years remaining

75 years

Annual ground rent

£200.00

GR capitalisation (est.)

£3,333.33

Reversion value (est.)

£12,000.00

Marriage value element (est.)

£2,250.00

Estimated premium (low–high)

£14,945.83 – £24,979.17

Highly simplified estimate only. Actual premiums require a specialist RICS leasehold surveyor using the Dearing formula. Professional costs (surveyor + solicitor ≈ £3,000–£6,000) are additional to the premium.

How Lease Extension Premiums Are Calculated

Quick Answer: The statutory lease extension premium has two main parts: (1) ground rent capitalisation and reversion value; and (2) marriage value: 50% of the increase in flat value created by the extension, triggered only when fewer than 80 years remain. Always instruct a specialist RICS surveyor for an accurate valuation.

The 80-Year Rule

When a lease has 80 or more years remaining, marriage value is zero, the premium is relatively modest. Once the lease falls below 80 years, the freeholder becomes entitled to 50% of the marriage value, which can add thousands or tens of thousands to the premium. Never let your lease fall below 80 years without extending or selling.

Formula

Premium ≈ Ground rent capitalisation + Reversion value + 50% Marriage value (if <80 years)

Marriage value = (Extended flat value − Short lease value) × 50%

Worked Example, £300,000 flat, 75 years left, £200/yr ground rent

Flat value£300,000

Years remaining75 years

Ground rent£200/year

GR capitalisation (est.)~£3,333

Reversion value (est.)~£12,000

Marriage value element (est.)~£7,500

Estimated premium range£15,000–£25,000

Rough estimate only. Actual premiums require a RICS leasehold valuation surveyor using the Dearing formula and comparable evidence.

Frequently Asked Questions

The premium (the price you pay the freeholder) for a statutory lease extension is calculated using the Dearing formula, which considers: the ground rent and term remaining; the reversion value to the freeholder; and marriage value if there are fewer than 80 years left. Typical premiums range from a few thousand pounds (long lease, low ground rent) to tens of thousands (short lease, high property value).