How Accurate Are Zoopla House Price Estimates?

Zoopla came onto the real estate scene back in 2007. One of its biggest draws for buyers and sellers is its “instant house price valuations” using its combination of data and algorithms to keep people informed about house prices. The company’s data from over 27 million homes is so extensive, it’s used by notable data platforms, such as the Urban Big Data Centre and Bright Data. 

However, it’s wise to remember that like all data, Zoopla’s comes with its fair share of variables. It’s why the company uses the word ‘estimate’, because that’s essentially what you’re getting when you see the eventual valuation. The company itself has stated online that although it sources data from “trusted and regulated sources” (e.g. HM Land Registry, Registers of Scotland, official survey records and Energy Performance Certificates), it may not take into account “recent extensions, renovations or makeovers”.  

If you’re here now, we can only assume you’ve recently received a house price estimate from Zoopla. Or you’re planning to get one and want to know a bit more about it. Whatever the reason, it’s always a good idea to do a little digging into these figures to determine their true accuracy. 

This is exactly what we’ve spent our time doing. Below, we’re going to dig into these instant house price valuations, including how they work. We’re also going to look at their accuracy and how realistic they are. 

Keep reading if you’d like to learn more about these house valuations.

Table of Contents

• What is a Zoopla house price estimate?

• How does it work with the data and algorithm?

• How do you go about getting an instant valuation online?

• How does Zoopla's valuation compare to other tools?

• How does the online price estimate compare to a traditional real estate listing?

• What causes online estimations to be inaccurate?

• How often does Zoopla update its price estimates?

• Why your Zoopla estimate could be lower than your neighbour’s

• What’s the difference between a Zoopla estimate and an RICS valuation?

• If not Zoopla, where or how should you get your house valued?

• Why is it so important to get an accurate house price valuation?

• Should you rely on Zoopla when refinancing your mortgage?

• How can The Property Buying Company help?

What is a Zoopla house price estimate?

A Zoopla price estimate is the value it believes your house is currently worth on the open market. You’re given a main ‘High Confidence’ figure with two figures (High and Low) on either side. This is the estimated range of your house’s value. It’s based on data and algorithms, which we’ll look at more closely now.

How does it work with the data and algorithm?

A house price estimate doesn’t involve anyone coming to view your property; it’s all done remotely and is generated by the company’s Automated Valuation Model (AVM). This proprietary algorithm was developed by Hometrack, one of the UK’s top property valuation platforms. 

The AVM creates its estimate by using data from various sources, including: 

1. Previous sold prices, including property characteristics, of homes around the UK (from HM Land Registry and Registers of Scotland)

2. Survey records from Ordnance Survey

3. Energy Performance Certificates

4. Google Maps data of property location, particularly nearby amenities (e.g. schools, parks and transport links)

5. Royal Mail data of localities 

Zoopla states that the data it uses “is updated every month”, but it can vary depending on the source. You can read all about the data and its relevancy in this article written by the company. 

It includes a couple of caveats in this article, most notably that “data is richer in England and Wales than in Scotland, where a narrower range of data is available, and in Northern Ireland, where it is not published.” 

It also states that the house price estimates are “not the same as a formal house price valuation from an estate agent or surveyor”, and that you should contact someone to provide a more accurate valuation during an in-person visit. 

As the Royal Institution of Chartered Surveyors (RICS) stated in their 2022 paper, ‘Automated valuation models insight’, “there is insufficient management and supervision by valuation professionals of AVM outputs produced by less-qualified personnel.”

This is just one of the many risks the RICS called out about AVMs in its paper, which is worth reading. They also concluded that human involvement is required when managing the outputs of AVMs, like the one Zoopla uses. 

“There are concerns from many participants that valuation and property professionals are not

sufficiently involved in the design, development, operation and governance of AVMs, given the idiosyncratic nature of many asset types being valued,” stated the RICS. 

This sentiment is echoed by, Jonny Christie, CEO of The Property Buying Company (TPBC) with over 20 years’ experience in property investment.

“Online estimates are good for getting an initial, rough estimate of the value of your home, but they are exactly that, rough. Majority of the time these estimates are inaccurate and will either under or overvalue your property depending on the metrics they use,” says Jonny.

“Getting a professional estimate will take a lot more factors into account and add that human element required for the knowledge of the area and, importantly, condition.”

How do you go about getting an instant valuation online? 

If you haven’t done one already, it’s really easy. Here’s a quick step-by-step guide using screenshots from a random valuation we got today:

There you have it. It’s really very quick and simple. Most importantly, you get a lot of great information about not only your property’s estimated value, but also the current market in your area.

It’s also honestly just fun looking back through the old photos of your home and seeing how it has changed over the years.

When you go through the main page with all the information, just make sure it’s all up to date. You may notice things missing. For instance, maybe you’ve added a bedroom or bathroom, but it’s still showing the old number. This changes can greatly affect your property’s value.

How does Zoopla’s valuation compare to other tools? 

This is a question you want to be asking from the beginning. When it comes to selling your house, knowledge is so valuable. You can gain more knowledge by comparing the figures you receive from Zoopla against other online tools, before arranging a professional in-person valuation. 

We were curious about how the figure for the property above would compare across different online tools. So we looked at the following options and compared them to Zoopla’s price.

Keep in mind that Mouseprice doesn’t look at individual properties, rather an average of a postcode area with the number of bedrooms and tenure and property type considered. So its price estimate is unsurprisingly the most different to the others.

But as we see, even a small different in valuation between Zoopla and Rightmove can result in you potentially overvaluing your house or missing out on £20,000.

How does the online price estimate compare to a traditional real estate listing?

For this comparison, we’ve looked at three different listings on traditional estate agents’ websites. We’ve tried to choose properties of varying types and in different locations, but it’s a small sample size so please don’t take it at face value. It’s really just an example of how Zoopla’s house price estimates can differ to professional valuations.

As you can see, the estimated price given online varies greatly depending on location and property value. For instance, the price given for the London property is a lot closer to the actual estate agent value. The data for a major city is potentially richer and more up to date than that of less populated areas. 

Remember, this is just a small sample size, but it does highlight the potential inaccuracy of Zoopla’s instant property valuation. These may seem like small percentages at first glance, but they equate to significant losses in value if you were to only rely on the online estimate. In the case of the second property above, you could lose out on £50,000 by only using the Zoopla valuation. 

The company is aware of these inaccuracies with its data, which is why it has that aforementioned disclaimer on its data explainer article.

What causes online estimations to be inaccurate?

When you’re relying on data that’s potentially one-month old, you have to be aware of certain inaccuracies. Zoopla does a decent job of getting its data from a lot of valuable sources and trying to keep it as updated as possible, but that 30-day (or longer) delay can leave some gaps. 

Outdated data is certainly one of the main reasons why online property valuations can be inaccurate. Some other reasons include: 

1. Market volatility

As we’ve experienced a lot recently, the UK property market is constantly going through changes. This volatility can mean that property values change from day to day or week to week. When an algorithm is using data that’s updated every month or couple of months, it can quickly become outdated compared to actual current property prices. 

2. Lack of local insights

In the current debate around human insight versus artificial intelligence, actual real estate agents and property evaluators possess a lot of value. When valuing your house or flat, there’s no replacing the local knowledge that many estate agents possess. 

An algorithm may not have the same level of nuance when it comes to your locality. Things like new developments, schools, more niche amenities or general foot traffic levels may only be known to an actual estate agent. 

3. Recent improvements to your property

Zoopla is the first to acknowledge that its data may not include any information around extensions or renovations that you’ve made to your property. These can greatly affect the value of your property. So if you’ve added a bedroom, modernised your bathroom or converted your loft into additional living space, you probably won’t see this reflected in an online valuation. 

For these reasons and more, it’s always good to use an ‘instant valuation’ as a guide. It’s great to have this figure in your head when you start talking to estate agents or a professional cash buyer like The Property Buying Company (TPBC). We’ll always do our own valuations, including an in-person assessment. But you’ll at least have a solid base of knowledge to work from. 

“The single biggest factor that most online estimates don’t take into account, or at least comprehensively enough, is condition,” says Jonny Christie, TPBC CEO. “The tools that are likely better are the ones that will ask you a few questions about the property’s condition and combine that with land registry data.” 

“There are so many things that go unaccounted for when using online calculators. You could be on a street that has a mix of different properties, with some being worth substantially more, due to unique features. But it would get down-valued online by similar properties on the street and there is no way an online tool could know that short of actually viewing the property.”

How often does Zoopla update its price estimates?

These online house value estimates are updated monthly, according to Zoopla, but not on the same day every month. Some of its data may also update less frequently than one month and it all “depends on where the information is coming from”. The company also states that “these trusted data sources may have incomplete information” and that it also “can’t always guarantee a complete match for all data points”. 

For this reason, Zoopla has three confidence ratings that may appear when you’re viewing your house price estimate: 

1. Low Confidence – You’ll see this when the data isn’t recent and there aren’t many comparable properties in your locality.

2. Medium Confidence – You’ll see this one when the data is “less up to date” and there are some similar properties around. 

3. High Confidence – You’ll see this when the data is considered “up to date” and there are a lot of nearby homes for comparisons.  

Due to these likely data discrepancies, Zoopla advises that “the estimate isn't the same as a formal house valuation from an estate agent or surveyor.” The company also says that they “always recommend speaking with an estate agent” when it comes to getting a proper valuation.

Why your Zoopla estimate could be lower than your neighbour’s

As we’ve mentioned earlier, there are numerous reasons why an online estimate might under or overvalue your property. This could mean that your valuation could be very different to your neighbours, which Zoopla acknowledges online. 

There are a few reasons for this: 

1. The data on your neighbour’s property might be more up to date, such as if they’ve recently moved in. This more recent sales data and affect online the AVM’s calculations. 

2. Your neighbour’s home might have very different characteristics to yours. The number of bedrooms, floorspace, garden size and other features can greatly change a property’s value. 

3. Zoopla’s AVM might not be accounting for any recent renovations or improvements you’ve made on your home. It may still be seeing your two properties as similar when in fact you’ve added a lot more value to yours. But if your upgrades are publicly available, the AVM should eventually pick them up. 

What’s the difference between a Zoopla estimate and an RICS valuation?

There are four key differences, which we’ll outline here:

If not Zoopla, where or how should you get your house valued?

We should be clear, we’re not saying you shouldn’t use an online valuation tool. It’s a great starting point. However, it should be used in conjunction with other valuation methods. 

Jonny Christie’s advice is to start by doing your own research, looking at your local market, seeing what nearby houses have sold for on Rightmove or another real estate platform. Then combining these figures with your knowledge of the local area.  

“The hardest part about doing this is if you own the property, you have a personal attachment and might struggle to see the condition subjectively. You really need to try and put yourself in the mind set of potential buyers and look at it without bias,” says Jonny. 

Here are some other options for valuing your property.

1. UK House Price Index

One of these is the Land Registry, which houses the UK House Price Index. As it states on the main page, the “UK House Price Index (HPI) uses house sales data from HM Land Registry, Registers of Scotland, and Land and Property Services Northern Ireland and is calculated by the Office for National Statistics.”    

You can use this data source to find out average property prices across the UK, specific countries, regions and local authorities. So for example, at the most granular level, you could look at property values in a local council like Brighton and Hove or Kensington and Chelsea. You can also look at data for specific property types (i.e. detached or terraced houses) and see how they compare. 

Source: UK HPI

 2. An RICS valuation

The Royal Institute of Chartered Surveyors (RICS) is the world’s leading organisation for maintaining the highest standards in property valuation. A chartered surveyor comes with a high level of expertise and knowledge. This extends to your local area. It can cost between £450 and £800 depending on your house’s value. A lot of owners don’t choose this option because of the price.

3. An experienced and local estate agent

You can enlist the services of one or multiple estate agents to value your home. Having multiple opinions can give you a better idea of your house’s price. You might also meet an agent you’d like to sell through during the process. 

5. Nationwide’s House Price Index calculator

One last option is to use Nationwide’s online HPI calculator. It’s a great tool for getting a good idea of your property’s value but it should also be used in conjunction with an actual in-person valuation. 

4. A professional cash buyer or online estate agent

Online estate agents, such as Purplebricks and 99 Home, will often provide a free in-person valuation of your property. The same can be said for legitimate and professional cash buyers. 

If you contact TPBC about selling your house or flat, we’ll usually send one of our expert consultants out to value your home in person. You won’t need to pay anything for this and you’ll be free to walk away afterwards if you’re unhappy with the price.

Why is it so important to get an accurate house price valuation? 

If the valuation of your home significantly under or overestimates its real cost, the impact could be quite serious. 

When selling your home, you no doubt want to get the best possible price. But you also don’t want your house stuck on the market for months and months. As we’ve seen in the above experiment with three properties around the UK, if your home is undervalued, you could miss out on thousands of pounds.

However, if you overvalue your home, it could deter potential buyers from taking it seriously on the market. In the UK, “the number of homes for sale is growing faster than the number of sales being agreed, boosting choice for buyers and re-enforcing a buyers’ market,” according to the Zoopla House Price Index. So there’s ample choice for buyers out there. If you want your house to attract them, you need it to be priced competitively and realistically in the current market. 

Should you rely on Zoopla when refinancing your mortgage? 

An online valuation tool should not be used in isolation when refinancing your mortgage. If your home is overvalued, you could end up overpaying on your mortgage or even having the loan denied due to the larger down payment required. 

It’s for this reason that the Financial Conduct Authority (FCA) states the following about remuneration and property valuation requirements for MCD creditors:

“An MCD creditor must use reliable standards for the valuation. Reliable standards for the valuation of residential immovable property include internationally recognised valuation standards, in particular those developed by the International Valuation Standards Council (IVSC), the European Group of Valuers’ Associations (EGoVA) or the Royal Institution of Chartered Surveyors (RICS).”

This is exactly why a Zoopla house price estimate should only ever be treated as exactly that: an estimate. Until you have undertaken an official valuation carried out by someone upholding the recognised industry standards, you should not assume to have complete and utter knowledge of your home’s price on the market. Doing so, could have significant impacts on you financially. 

How can The Property Buying Company help? 

Are you wanting to sell your house or flat fast? We offer various options for selling your house quickly, tailored to your timeline. If you get in touch with us about your property, we’ll typically conduct two valuations. 

The first one will be performed using data and our own expert knowledge. If you’re happy with this initial valuation, we’ll then send one of our experienced Property Consultants to assess your home in person. The best part about all this is we’ll do it for free.

After this second valuation, we won’t just give you an answer as to what we feel your property is worth, we will buy your property for this amount in cash, with all your fees included. We buy any property in any condition and location. Our Property Consultants are also experienced in working with a variety of customers who need a quick sale for many different reasons. 

We will always be open and honest about our service and process. Our goal is to help you sell quickly while still getting the best possible price.