Lease Extension Calculators vs. Real Valuations: Why Accuracy Matters
When thinking about extending a lease, many leaseholders start by typing figures into an online calculator and while that can be a useful starting point, it rarely tells the full story. At Olden Property, we often meet clients who’ve received very different premium estimates depending on where they looked. The truth is that lease extension valuation is part science, part interpretation and context makes all the difference.
Why online estimates fall short
Most online lease extension calculators work on simplified formulas. They use average relativity rates, generic capitalisation and deferment rates, and assume typical ground rents and flat values. In reality, none of these are fixed. A seafront flat in Brighton, a conversion in Tunbridge Wells, and a modern block in Maidstone could all produce very different results, even with the same lease length.
These calculators rarely reflect the nuances that drive value: floor level, condition, location within a town, parking, outside space, or even the wording of your lease. When it comes to negotiation, those details matter and they’re exactly what a RICS valuer will analyse in depth.
The importance of real market evidence
Every professional lease extension valuation starts with comparable sales, recent transactions of similar flats with varying lease lengths. We analyse how market value changes as the term shortens, building a relativity curve specific to your property type and location. That’s how we determine a fair premium that stands up to scrutiny from both leaseholder and freeholder sides.
An inaccurate starting figure can lead to overpaying or underestimating, both of which can stall negotiations or cause unnecessary disputes.
Negotiation strength comes from credible evidence
When you serve a formal Section 42 Notice, your proposed premium must be supported by evidence. A report prepared by a RICS Registered Valuer not only provides that foundation but also gives you leverage in discussions. If the matter proceeds to the First-tier Tribunal, the valuation report becomes your key piece of evidence, far more reliable than an online estimate.
Getting clarity early
Even if you’re just considering your options, commissioning a formal valuation now can help you plan ahead, whether you’re budgeting for the premium, preparing to sell, or coordinating with your solicitor.
At Olden Property, we provide independent, RICS-compliant lease extension valuations across Kent, Sussex, Surrey and Greater London, combining local market evidence with statutory methodology to deliver accurate, defensible advice.
Contact us today for a clear, professional view of your lease extension premium.