Published 6 June 2026 · By James Chandler · 6 min read

Land Registry HPI vs Zoopla: why your home's value is wrong

Zoopla shows one number. Rightmove shows a different one. Your mortgage lender uses a third that's usually higher than both. They can't all be right. Here's the one that actually matters — and how to calculate it yourself in five minutes.

If you've ever checked your home on a property portal, you'll have noticed something odd. Type your address into Zoopla and you get an estimate, in pounds, with two decimal places, as if it were a precise fact. Do the same on Rightmove and you'll get a different number. Sometimes the gap is small. Sometimes it's £40,000.

Both portals are pretending to know something they don't. Neither has been inside your home. Neither knows the work you've done to it. Their numbers are guesses, generated by a model, presented with the calm confidence of a bank statement.

This article is about a better way to think about what your home is worth — using the same source mortgage lenders actually use behind the scenes.

What Zoopla and Rightmove are actually doing

Both portals run something called an Automated Valuation Model, or AVM. It's a piece of software that ingests millions of property listings, sold prices, and neighbourhood data. It then tries to predict what your specific house would sell for if it went on the market today.

AVMs are good at a few things. They're fast. They produce a plausible-looking number for almost any UK address. They update frequently. For getting a rough sense of a market or browsing properties, they're fine.

They're poor at other things. They can't see inside your house, so they don't know whether you've extended, renovated, or let it fall apart. They're trained on listing prices (asking prices), not the prices homes actually sell for. Their methodology is proprietary — you can't check it. And critically, they're not what anyone making a real financial decision uses.

What lenders use instead

When a lender decides how much you can borrow, what loan-to-value band you sit in, or what risk weighting to apply to your mortgage, they don't pull a number off Zoopla. They use one of two things: a paid surveyor visit (slow and expensive) or the UK House Price Index, published monthly by HM Land Registry and the Office for National Statistics.

The HPI is the official statistic. It's free. It's published. The methodology is documented. You can browse the data yourself at gov.uk right now if you want to. And it works in a much more honest way than AVMs do.

How the HPI actually works

Instead of guessing the value of any individual house, the HPI tracks what's happened to the prices of real, sold houses in your area over time. The methodology, called repeat-sales regression, looks at homes that have been bought and sold more than once. By comparing sale prices of the same property in different years, it teases out how much house prices in that area have moved, separate from the impact of different houses being sold.

The result is a percentage. Houses in your local authority, of your property type, went up (or down) by X% in the time you've owned. That number, applied to your actual purchase price, gives you a defendable estimate of what your home is worth today.

A worked example

Compare that to whatever Zoopla or Rightmove tells you for the same address. Sometimes they agree. Often they don't. When they don't, the HPI number is the one a lender, a surveyor, or a serious financial planner will treat as the baseline.

The two things to know about HPI

1. It lags by two to three months

The HPI is published with a delay, because it depends on Land Registry recording all the sales in a month before it can be calculated. So the "latest" HPI you can use today reflects market conditions from a few months ago. For long-term net worth tracking that's fine — you're not trying to spot a moment in time, you're tracking a trajectory. But if the market is moving fast, your HPI-based estimate will trail reality by a quarter or so.

2. Local matters more than national

You'll often see headlines like "UK house prices rose 4% this year." That's the national HPI. It's an average across hundreds of areas, and it can mask huge regional differences. Always use the HPI for your specific local authority district, not the national figure. Your home is in a particular borough or district, and that's the level at which the index is meaningful.

When to use which number

None of this means you should throw Zoopla in the bin. Each tool has a use.

• For tracking your net worth: use the HPI. It's the closest thing to truth without paying for a surveyor.
• For thinking about putting your home on the market: use Zoopla or Rightmove as a sanity check on what similar homes are being listed for, then get an actual estate agent valuation.
• For making a real sale: the only number that matters is what a buyer will pay, which you discover by listing.

For everything else in between — should I overpay my mortgage? Am I closer to the next loan-to-value band? What's my equity stake? — the HPI is the right answer.

Doing this yourself takes five minutes

The HPI tool at gov.uk is genuinely free and genuinely usable. Plug in your local authority, find the index value for the month you bought, find the latest value, divide one by the other, multiply by your purchase price. That's it.

The annoying part is the upkeep. The HPI updates monthly. House prices move. Your mortgage balance changes. The number you calculated today will be slightly wrong next month. Keeping a current view requires you to do this calculation often enough that you remember to do it at all — which most people don't.

If you want to see what your home equity does to your wider picture in 60 seconds, try the free Wealthly net worth calculator — it includes a property field so you can slot the HPI-derived value straight in.

That's the gap Wealthly fills. It pulls the latest HPI for your area automatically, applies it to your actual purchase price, subtracts your mortgage balance, and shows you a current home equity number you can trust without doing any maths. You can also override it if you've done major work and you know the AVM has missed something.

More reading: Your real UK net worth: 5 assets every other app misses · DB, DC and State Pension: how to track all three in one place · Best net worth tracker UK: Emma, Snoop, Aureli & Wealthly compared