How UK Property Valuations Actually Work

"What's my house worth?" gets answered at least three different ways in the UK property market, and it's worth knowing how each one actually arrives at a number.

1. Automated valuation models (AVMs)

Tools like this one work by finding recent sales of comparable properties near yours, adjusting each one to today's prices using a house price index (since a sale from three years ago needs scaling up or down to reflect how the whole market has moved since), and taking the median. The result comes with a confidence score based on how many comparables were found, how close by, how recent, and how much they agree with each other.

What an AVM can't see: the inside of your property. It doesn't know about your extension, your damp problem, or your new kitchen — it only knows what similar properties nearby have sold for.

2. Estate agent appraisals

An agent valuing your home for sale combines the same comparable-sales logic with local market knowledge (what's actually selling right now, not just what sold historically), and a physical look at your property's condition and any improvements. Agents also have a commercial incentive to give an optimistic figure to win your listing — worth bearing in mind when comparing an agent's appraisal to an AVM's more dispassionate number.

3. RICS surveys and mortgage valuations

A formal valuation by a RICS-qualified surveyor is the most rigorous: a physical inspection, professional judgement on condition and any defects, and a valuation that a mortgage lender is willing to lend against. This is what actually determines whether a sale can complete at the agreed price. See our guide on RICS surveys vs online valuations for more detail.

The common thread: comparable sales

All three methods ultimately lean on the same underlying idea — what have similar properties actually sold for recently, nearby? The differences are in how rigorously that comparison is done, how much local/physical knowledge is layered on top, and how much of an incentive the person or system giving you the number has to be right versus favourable.

What actually moves the number

Across all methods, the biggest factors are: location (down to the street, sometimes), property type and size, condition, tenure (see our leasehold vs freehold guide), and how recently comparable properties have sold. See our full guide on what affects property value for a complete breakdown.