Which house price index should you believe?

In any given month the UK’s main house price measures will disagree, sometimes about the direction as well as the size of the move. That is not a sign that some of them are wrong. Each one counts a different set of homes at a different stage of the same transaction, and the official index says so itself: Rightmove uses asking prices, Nationwide and Halifax use their own mortgage approvals, and the UK House Price Index uses completed sales at the end of the conveyancing process. Once you know which stage a number describes, the disagreements stop being contradictions.

Why do they disagree?

A house sale is a sequence, and each measure taps it at a different point. A seller sets an asking price. Offers are made and one is accepted. A lender values the property and approves a mortgage. Contracts exchange. The sale completes. It is registered. Between the first step and the last, months pass, the price usually changes, and roughly a third of buyers never appear in any lender’s data at all because they are paying cash.

So the question is never “which index is right”. It is “which stage, and which buyers, am I asking about”.

What does each one actually measure?

Three consequences follow from that table and they explain most of the monthly noise. Asking prices lead completed prices by months, so Rightmove turns first and is the least reliable guide to what anything sold for. Lender indices exclude cash buyers, who are roughly a third of the market and are concentrated at the older and the wealthier ends of it. And the official index is the most complete and the slowest, because a sale only enters it once it has been registered, which takes weeks to months after completion.

Which one answers your question?

• Is the market turning? Asking prices first, then approvals. They are early and they are noisy, and being early is the whole of what they are for.
• What is the market doing, properly measured? The UK House Price Index. It is the most complete measure of the whole market and it is the one to quote when the answer matters more than the timing.
• What did homes actually sell for near me? Sold prices, at the smallest grain you can get. An index tells you about change; it does not tell you what anything cost.
• Is this asking price reasonable for this home? None of the indices. They are all averages over populations, and judging one property needs a local rate and a size, not a national percentage.

Where do this site's figures sit?

RealScout is not an index publisher competing with the ONS, and it would be a poor one: the official index is more complete, better resourced and revised properly. What this site publishes is the thing an index cannot give you, which is a level at a small grain. The median home sold in England & Wales in the 12 months to June 2026 went for £3,380 per square metre, across 474,766 matched sales, and the same figure exists for every postcode district.

A rate is a different instrument from an index. An index answers “how much has the market moved”. A rate answers “what does a square metre cost here, now”, which is the question you need answered when you are looking at one house. This site also publishes a repeat-sales index, not to compete with the official one but as a check on its own rate: if the two disagree about a region’s decade, that is worth knowing before either is quoted.

Which limitation do they all share?

Every measure above is published in cash terms by default. Over a decade in which consumer prices rose substantially, a series that is flat in cash is falling in real terms, and almost every headline you will read takes the cash number. The gap between the two is often larger than the difference between any two of these indices, and it is the correction least often applied.

They also share a second limit, which is that none of them describes a house. They describe markets. The moment the question becomes a specific property, the right tools are a local rate, a floor area and an understanding of which average you are being shown.