For UK leaseholders

Free Leasehold Premium Calculator

Estimates the statutory premium to extend a leasehold flat or house by 90 years under the Leasehold Reform Act 1993. Three relativity graphs (Gerald Eve, John D Wood, Savills) give a low / mid / high spread. Methodology is documented in full below.

Freehold value = the value the property would have if it were freehold or had a very long lease. Often called the “unimproved value” in tribunal documents.

Estimated premium

Realistic spread

£24,654 to £43,779

Mid estimate: £32,529

Gerald Eve 2016 (tenant-friendly)

£24,654

John D Wood 2011 (middle ground)

£32,529

Savills 2002 (landlord-friendly)

£43,779

Components (mid estimate):

Reversion: £11,588

Capitalised ground rent: £4,114

Marriage value: £16,971

When to extend

Below the 80-year threshold. Marriage value applies, which significantly increases the premium. Every year the lease ticks down adds an extra few hundred pounds to the premium. Initiate the statutory process now if you intend to extend at all.

For free, independent guidance from the government's leasehold service, see the Leasehold Advisory Service (LEASE).

Methodology

The statutory formula under the Leasehold Reform Housing and Urban Development Act 1993 (as amended in 2002) values the freeholder's loss in three parts: (1) the reversion (present value of the freehold reverting at the end of the lease), (2) the capitalised ground rent stream, and (3) the marriage value (50% of the value uplift created by the extension, applicable only when fewer than 80 years remain).

We use the Sportelli deferment rate (5% for flats, 4.75% for houses) and a 6% capitalisation rate for the ground rent, both of which are the well-established UK Upper Tribunal norms.

Three relativity graphs are surfaced so the spread is honest. Gerald Eve 2016 produces the lowest premium, John D Wood 2011 sits in the middle, and Savills 2002 produces the highest. Tribunals routinely choose between or interpolate across these graphs, so a real premium typically lands inside the spread.

What this does not include: compensation for any onerous lease terms (e.g. doubling ground rent every 10 years), professional fees on both sides (typically £2,500-£5,000 combined), or specific lease provisions that affect freehold reversion value.

What this tool tells you

  • A realistic premium range, not a single point estimate, because real-world tribunal outcomes have a real spread.
  • A timing recommendation, based on the 80-year marriage-value threshold.
  • Component breakdown so you can see exactly what makes up the premium (reversion, ground rent, marriage value).
This is an estimate, not legal advice. Real premiums depend on the specific lease terms, the negotiation between you and the freeholder, and the relativity graph a tribunal ultimately accepts. Commission a formal valuation from a chartered leasehold valuation surveyor before serving a Section 42 notice.

Buying or selling a leasehold property

The Premium-tier property report includes a full leasehold analysis: years remaining, extension cost band, mortgage risk, freeholder profile and service charge benchmark. From £24.99.

See the Premium sample report