Barely a month goes by without a fresh house price index headline, often with different sources reporting seemingly contradictory figures on the same day. Understanding what each index actually measures makes these reports far more useful — and much less confusing.
The main UK house price indices
- Halifax House Price Index: Based on Halifax's own mortgage lending data, published monthly and among the earliest indicators available each month
- Nationwide House Price Index: Similarly based on the lender's own mortgage approvals, also published monthly
- UK HPI (Land Registry / ONS): Based on actual completed property transactions registered with HM Land Registry, generally considered the most comprehensive but published with a longer lag, since it relies on completed sales data
- Rightmove House Price Index: Based on asking prices at the point of listing, not completed sale prices — useful for gauging seller sentiment, but not what buyers actually end up paying
Why the figures often disagree
Different data sources, different regional weightings, different points in the buying process (asking price vs mortgage approval vs completed sale), and different sample sizes all mean indices can tell noticeably different stories in the same month, especially over short periods.
National figures vs your local market
National averages can mask significant regional variation — a national figure showing modest growth can sit alongside some regions rising meaningfully and others falling. If you're buying or selling, regional and even local-authority-level breakdowns (which most major indices also publish) are usually far more relevant than the national headline.
Annual change vs monthly change
Monthly figures can be volatile and are sometimes revised in later reports; annual change figures smooth out some of this noise and tend to be a more reliable gauge of the underlying trend, though they naturally lag behind very recent shifts in the market.
What house price trends mean for your mortgage decisions
House price movements affect your loan-to-value ratio over time, which in turn can affect the mortgage rates available to you at remortgage. A property that's risen in value may put you in a lower LTV band and unlock better rates; a falling market can have the opposite effect, which is worth factoring into your remortgage timing.
You may also find our guides on Mortgage Rate Predictions: What Could Happen Next and Best Low-Deposit Mortgage Options Explained useful.
To run your own numbers, try our Mortgage Affordability Calculator.
The bottom line
House price indices are a useful barometer, but only when you understand what each one is actually measuring and treat single-month figures with appropriate caution. Look for trends confirmed across more than one index and, where possible, at the regional level relevant to you.