House price indices: which one should you trust?

The housing market has four different house price indices which regularly tell their own story on property values. Paul Thomas looks at which one you can trust.

Why does every house price index tell a different story? You often find that while one says prices are climbing, another insists they’re falling. A third might suggest that the market’s holding steady.

If you follow the UK housing market even in passing, you’ve probably wondered why they all seem to say different things.

The reason for that is each house price index (HPI) uses different data sources and methodologies to come to their conclusions.

So, which one should you believe?

To help you cut through the noise, Mouthy Money has unpacked the four most commonly used indices, looking at how they work, what they’re good for and where they fall short.

Once you understand how each one ticks, you’ll be better equipped to read the market – and the headlines – with confidence.

Halifax House Price Index

Methodology

The Halifax HPI is the UK’s longest-running monthly house price series, with data going back to January 1983.

But how does it work?

Halifax is the UK’s largest mortgage lender. Every time it offers a mortgage to someone buying a home, it collects detailed information about the property, including the price, location, size and type.

It takes that data to arrive at a ‘standardised’ average price, which adjusts for differences in the types of homes being sold.

This helps avoid misleading spikes or drops in the average price that might happen just because more expensive or cheaper homes happened to sell that month.

What it’s good for

The Halifax HPI is one of the most up-to-date snapshots of the UK housing market, released just a few working days after each month ends. For instance, data for June 2025 was published on 7 July.

As one of the UK’s biggest mortgage lenders – responsible for around one in five mortgage approvals – Halifax draws on a large and reliable sample of real sales. That gives the index strong credibility and makes it a good indicator of emerging trends in the housing market.

Because the index is published monthly and based on a consistent methodology that’s been used for decades, it’s also a useful tool for tracking long-term shifts in house prices.

Drawbacks

The biggest drawback is that the Halifax HPI it doesn’t cover all property transactions, only those where the buyer purchased their home with a Halifax mortgage.

That means it excludes most transactions, including cash buyers, which account for roughly 30-40% of all property sales, or anyone buying with a mortgage from another lender.

Secondly, it only measures mortgage approvals, not completed sales. That means it reflects the price agreed at the point a buyer’s mortgage is approved, often weeks before the deal actually completes.

As a result, it may not always capture last-minute price changes, fall-throughs or renegotiations that happen later in the process.

What does the latest Halifax HPI say?

You can find the latest Halifax HPI data here.

Nationwide House Price Index

Methodology

Nationwide also produces a highly regarded and long-running HPI, with data stretching back to 1952.

Like Halifax, it uses its own mortgage approval data to compile the index, rather than completed sales.

Again, similar to Halifax, its headline house price figure is based on a ‘typical’ UK house, which it tracks over time.  

This stops the data being skewed if an unusually large number of cheaper or more expensive houses come to market at the same time.

What it’s good for

Nationwide’s HPI is extremely up to date, with the index published days after the end of the previous month.

Its consistent approach makes it valuable for identifying turning points or early shifts in market sentiment. The bank also provides useful commentary and longer-term trend comparisons in its monthly reports.

Drawbacks

The drawbacks with Nationwide’s HPI mirror those of Halifax’s, in that it doesn’t capture the whole of the market, only those buying with a Nationwide mortgage, and it is only based on mortgage approvals.

Unlike Halifax, it doesn’t include buy-to-let transactions, either, leaving out a sizeable chunk of the market.

Nonetheless, Nationwide is one of the largest mortgage lenders in the UK, meaning it’s sample size is relevant and therefore acts as a useful barometer of activity.

What does the latest Nationwide HPI say?

You can find the latest Nationwide HPI data here.

UK HPI

Methodology

The UK House Price Index (HPI) is the ‘official’ measure, produced by HM Land Registry, in partnership with the Office for National Statistics (ONS), Land & Property Services Northern Ireland and Registers of Scotland.

Unlike the Halifax and Nationwide HPIs, it looks at completed sales, including both mortgage and cash purchases, and adjusts for things like property type, location and whether it’s a new or existing home.

What it’s good for

This is the most accurate and comprehensive measure of UK house prices, offering full market coverage and a highly detailed breakdown by region, buyer type, tenure and property type.

It’s ideal for policy analysis, academic research and serious market insight. The inclusion of cash buyers – often missing from other indices – makes this a more complete reflection of the housing market as a whole.

Drawbacks

The main disadvantage is the time lag. The index is usually published six weeks after the end of the month, which means it’s not useful for tracking immediate changes. For example, April 2025’s figures were published on 18 June 2025.

Figures for the most recent month are often provisional and subject to revision as more transactions are registered. It also tends to receive less media coverage, as journalists prefer faster-moving indicators.

What does the latest UK HPI say?

You can find the latest UK HPI here.

Rightmove HPI

Methodology

The Rightmove HPI is different from the others outlined above, in that it measures asking prices, rather than approvals or values recorded upon completion.

In other words, the index reflects seller expectations, not final sale prices. It also doesn’t account for price reductions made after the listing goes live.

Most estate agents list properties on Rightmove, giving it a huge sample size of around 100,000 properties a month.

What it’s good for

Rightmove’s index is the fastest to publish, typically released within the same month it covers.

It’s a useful measure of seller confidence, showing how optimistic people are when pricing their homes for sale, making it helpful for both buyers and sellers to gauge market sentiment.

Drawbacks

The index shows asking prices — what sellers hope to get — rather than what homes actually sell for. This means it often sits above real market values and doesn’t reflect agreed or completed sale prices.

What does the latest Rightmove HPI say?

You can read the latest Rightmove HPI here.

Which house price index should you pay most attention to?

Choosing the right house price index depends on what matters most to you.

If you want absolute accuracy and a full picture of the market, the UK HPI is your best bet.

It covers all sales – mortgage and cash – across every region and property type, reflecting the actual prices buyers pay.

If timeliness is your priority, and you want to track the market’s latest momentum and buyer sentiment, Halifax and Nationwide indices offer valuable early insights.

Both draw on significant mortgage lender data (although considerably smaller than the UK HPI) and release updates shortly after month-end, making them great for spotting short-term trends and market shifts.

If you’re interested in seller behaviour and pricing expectations, the Rightmove HPI is your best bet. Because it’s based on asking prices from hundreds of thousands of new listings, it shows how confident sellers are in the market, which can be a useful leading indicator. But remember, asking prices don’t always reflect what homes actually sell for.

Ultimately, using these indices together can provide the richest understanding. Combining Rightmove’s early signals, Halifax and Nationwide’s mortgage-backed data, and the ONS/Land Registry’s official transaction figures creates a fuller, multi-angle view of the UK housing market.

All facts and figures in this article are correct as of 10 July 2025.