Home value websites can give you a rough ballpark estimate of a property’s value. But they’re simply not reliable enough to make any meaningful decisions, like setting a list price or submitting a purchase offer. Even the best home value estimators are frequently off by tens of thousands of dollars.
Zillow’s Zestimate tool is the best free online home value estimator, but that’s not saying much. While Zestimates are, on average, slightly more accurate than most alternatives — and cover the largest geographical range — they still have a wide margin of error.
Messing around with online home value estimators is fun, but when you’re ready to sell, we recommend getting a comparative market analysis (CMA) from a local realtor. Unlike a home value estimator, a CMA is based on an in-person visit to your home, and therefore, is much more accurate. A good agent will provide a CMA for free before you even sign a contract, so there’s no risk or obligation.
» In this guide, we’ll look at:
- The most popular home value websites ranked
- How accurate home value estimators are
- How to get the most out of a home value estimator if you’re selling
- How to use a home value estimator if you’re investing or buying
- Our methodology
Top free home value estimators
Zillow and Trulia
Our take: Zillow’s Zestimate covers almost every corner of the U.S. and is more accurate than most of the competition, but it’s really only the best of a bad lot.
Zillow’s — and its sister site Trulia’s — Zestimate is the most popular online home value estimator and the best overall. But being better than the competition isn’t saying much. Our mystery shoppers and researchers give it a grade of B — good, but not great.
Zestimate has a national median error rate of 6.9% for off-market homes and 1.9% for homes that are already listed. If you’re thinking about selling, your home is probably still off market, so you should assume that the off-market rate — the less accurate one — applies to you.
🚨 That error rate is worse than it looks
Most home value estimators publish their median error rate — if they provide one at all. Median error rates are a bit misleading, hiding the fact that home value estimators are often way off.
Here’s why: with a median error rate, only 50% of homes fall within the published error range. The other 50% of homes will have an even higher error rate. So if you put your off-market home into Zestimate, there’s a 50/50 chance that the home value you’ll get will be WORSE than Zestimate’s 6.9% error rate.
While Zestimate isn’t that accurate — and no home estimator is — it does get points for having a lot more coverage. It doesn’t cover every property in the country, especially not rural areas, though it does have estimates for 104 million homes, or about three-quarters of all homes in the U.S.
Our take: Redfin Estimate scores points for accuracy, but with limited coverage outside of cities, it’s not the most widely useful home value estimator.
Redfin’s home value estimator, Redfin Estimate, is slightly more accurate than Zillow’s Zestimate for off-market homes and slightly less accurate for currently listed homes.
Redfin Estimate has a median error rate of 6.68% for off-market homes and 2.49% for on-market homes. So unless your home is already on the market, Redfin is likely going to be more accurate for you than Zillow’s Zestimate.
We give Redfin Estimates a B–, slightly behind Zillow. That’s because Redfin Estimate has less coverage, with estimates for just 92 million homes — 12 million fewer homes than Zillow. So despite its greater accuracy, Redfin Estimates is effectively useless for millions more people than Zestimate is.
We encountered this coverage problem firsthand when testing out both estimators. When we input randomly selected properties into Redfin Estimate, the estimator struggled to find many of the properties we were able to easily find on Zestimate — especially ones in small towns and rural areas.
Our take: Realtor.com claims to use industry-leading estimates, but since it doesn’t publish its average error rate, it’s impossible to say how accurate it really is.
Realtor.com claims its home estimator uses data from three different sources: CoreLogic, Collateral Analytics, and Quantarium — all of which are used by mortgage lenders to help determine home values. That might sound impressive, but we found no evidence that Realtor.com is more precise than other home value estimators.
In fact, unlike Zillow and Redfin, Realtor.com doesn’t share its median error rate, so it’s impossible to know how accurate its valuations are. Until Realtor.com shares its error rate, as Zillow and Redfin do, we give its estimator a score of C+.
The fact that Realtor.com uses the same data sources as mortgage lenders isn’t proof that those data are more accurate. Mortgage lenders require an in-person appraisal before approving a mortgage. They aren’t going to be making lending decisions based on an algorithm.
And you shouldn’t be making major decisions based on an algorithm either. Hiring a real estate agent to perform a comparative market analysis (CMA) is the best way to get an accurate home value estimate. And unlike an online home value estimator, they have the same goal you have: selling your house for the best price possible.
Our take: HomeLight’s home value estimator is nothing more than an excuse for HomeLight to get your phone and start spamming you with phone calls. Avoid.
Of the big four home valuation websites, HomeLight is our least favorite and the only one we recommend actively avoiding. If you do use it, expect to get spammed.
Unlike with the other home value estimators we tried, we had to provide our phone number to get our home value estimate from HomeLight. Almost immediately after doing so, we were inundated by calls from HomeLight representatives trying to match us with a HomeLight partner agent.
If you want to avoid getting spammed like this, use any of the other three home valuation websites we looked at above.
What’s worse, HomeLight doesn’t publish its home calculator’s error rate, so there is no way to know how accurate it is.
In the tests we ran, HomeLight generally produced the lowest or second-lowest home valuation estimates. While that’s not necessarily proof that HomeLight is less accurate, it suggests that HomeLight may be using outdated information.
Because the housing market has been red hot over the past year, an estimator that uses sales data going too far back will produce lower home estimates. This may be what’s going on with HomeLight, but since HomeLight doesn’t publish its error rate, we can only speculate.
Paid home value estimators
Other companies offer paid home value estimates, such as Attom Data, Black Knight, and Ownerly. These companies typically promise greater accuracy along with way more data about a property than you would get with a free home value estimator.
However, if you’re looking to sell your home, there’s no point paying for an estimate. A real estate agent can get you a far more accurate CMA for free and with no obligation.
Most paid home value estimators are marketed toward real estate professionals, such as brokers and investors. If you are considering buying a new investment property, then a paid estimator may provide some value.
Unfortunately, none of the paid estimators share information about the accuracy of their estimates, so it’s impossible for us to recommend one over the other.
Other home value estimators
There are countless other home value estimators out there, but most of them are nothing more than rebranded versions of one of the four above calculators.
That said, they’re almost always free and some do use slightly different algorithms from the big four. A few do require you to provide contact information to get your home value estimate. We don’t recommend doing that unless you want to get inundated with endless calls and emails.
If you’re curious, here are some of the most popular online calculators not covered in this review:
How accurate are home value estimators, REALLY?
The bottom line is that home value estimator tools are not accurate. On average, online estimators have a median error rate of approximately 2–7%. That might not sound like much, but it can represent tens of thousands of dollars on a home sale. Plus, the error rate gets even worse depending on where you live, whether or not your home is already listed, how long ago you bought it, and whether it was recently renovated.
The problem with all estimator tools is that their assessments are based on how much “similar” properties have sold for near you. Algorithms need to make assumptions about your property that may or may not be true, which inevitably leads to mistakes.
For example, two properties may appear to be exactly the same to an algorithm, but if one has a renovated kitchen, that can add $20,000 extra to the list price.
We tested the four most popular home value estimators — Zestimate, Redfin Estimate, Realtor.com, and HomeLight — using dummy addresses in a city, a suburban area, and a rural area to see how different the estimates were for each property.
As you can see, the difference in estimates was huge — over $53,000 for our city property! That just goes to show that online home value estimates are not reliable for pricing your home properly.
To get a far more accurate estimate of your home’s value, you need to consult a real estate agent and get a free CMA.
Why your home value estimate may be even less accurate
You may live in:
Your house is in a hot property market
Living in a hot housing market can make a home value estimator both more and less accurate.
Algorithms rely on previous sales in your neighborhood to determine what your house is worth. If the algorithm uses outdated sales data — which, in a hot housing market, can be as recent as 6–12 months ago — that can mean your estimate will be way off.
For example, Zillow Zestimates has its largest margin of error for active listings in Seattle and San Francisco — two of the hottest real estate markets in the country.
Hot housing markets can sometimes make estimates more accurate, however, simply because there tend to be a lot of sales. More recent sales data to pull from usually means smaller margins of error.
Unfortunately, no home value estimator publicizes how far back they go when looking for comparable properties, so there’s no way to know for sure which estimator works best in a hot market.
Your house is in a slow or rural property market
Just as a hot housing market can wreak havoc with an estimator’s algorithm, so can a slow one where there are likely to be fewer sales, like in a rural market. When fewer houses are being bought and sold, estimators have less sales data to rely on.
With less data, just one or two home sales can skew an algorithm. If those homes don’t share a lot in common with your home, then expect your estimate to be off.
Because fewer homes are sold, a home value estimator may also have to rely on older sales data, which again will cause the estimator to be less accurate.
If you’re trying to sell in a slow market, take any online home value estimator with a grain of salt. When you’re serious about selling, contact an agent to provide you with a far more accurate idea of what your home is worth.
You live near many different types of houses
Home value estimators work by comparing your property with similar properties that have sold nearby. That tends to work well if you live in a neighborhood where most of the properties are genuinely similar.
But if your neighborhood features a mix of different property types, the algorithm may rely on sales data from properties that aren’t much like yours. This tends to be a more common problem in older neighborhoods and city centers.
For example, you may live in an urban neighborhood that has a mix of single-family homes, row houses, and condominiums, with construction dates ranging from a hundred years ago to last year. Although algorithms do try to control for this variety, there’s a much higher chance that they’ll miss the mark and end up basing your home value estimate on nearby properties that are dissimilar to yours.
In contrast, home value estimators tend to be more accurate if you live in an area with a more homogenous housing stock. For example, a suburban subdivision where all of the properties are roughly the same style, size, and age will present fewer difficulties for an algorithm.
Your house has unique characteristics or features
Houses that look the same on paper aren’t necessarily the same from a buyer’s perspective. A unique home feature can affect how much you can list it for, for better or worse.
Unfortunately, many unique features — such as a stunning view or proximity to a busy road — can be difficult for an algorithm to pick up on.
Even renovations — which algorithms do try to account for with varying degrees of success — can be hard for a home value estimator to judge accurately.
For example, two houses may be listed as having “renovated kitchens.” But if one renovated kitchen features the latest appliances and high-end materials and the other was renovated with cheaper materials, the difference can translate into tens of thousands of dollars.
A real estate agent performing a comparative market analysis can pick up on those differences right away and adjust your estimated home value accordingly. An algorithm can’t, which is why many of them are often off by so much.
You live in a state where sales data isn’t public
All home value estimators rely on publicly available data, like sales records, to come up with their calculations. However, not all states make real estate transactions public record.
In states where house sale records are not publicly available, home value estimators have less data to rely on, which means they’re more likely to be way off. In many non-disclosure states, home value estimators aren’t even available at all.
If you live in a non-disclosure state, take home value estimators with a large grain of salt.
If you’re looking to sell your house, you will want to reach out to a real estate agent to get a more reliable estimate of what your house is worth.
Who should use a home value estimator?
We don’t recommend using home value estimators to actually buy or sell a property. They’re simply not accurate enough. That said, they can be somewhat useful in a few situations.
- Home sellers: Home value estimators can provide a ballpark estimate of your home’s value, so you can decide if now is the right time to sell.
- Property investors: Estimators can give you some data to use as a starting point when modeling potential deals.
- Home buyers: Estimators can help in negotiating the sale price — especially with for-sale-by-owner homes — if the listing price seems too high.
While they can be a fun tool, to find the true value of a home we highly recommend getting a CMA from a local realtor.
Should I use a home value estimator if I’m selling?
For sellers, a home value estimator will give you a ballpark estimate of what your home may be worth, but don’t rely on it to set your list price. Home value estimators are inaccurate and a real estate agent will be able to provide a more accurate estimate for free with a CMA.
Why getting an accurate home value estimate matters
Getting an accurate home value is one of the most important steps in selling your house — and, in some cases, buying a house.
As a seller, an accurate home value is going to be the main data point you use to price your home. If that home value estimate is off, then it could come back to bite you.
Price your home too high, and you’ll struggle to find buyers or your home may languish on the market. Price it too low, and you could miss out on tens of thousands of dollars.
How to get the most accurate home value estimate
The best way to get the most accurate home value estimate is through a CMA by a real estate agent.
A CMA is completely free and comes with no obligations. You can ask an agent for a CMA without actually having to commit to using that agent to sell your house.
In fact, we recommend getting CMAs from two or three realtors. That way, you can get an even more accurate home value estimate while also comparing different realtors to see who you think is the best fit for you.
Why are CMAs better than online estimators?
CMAs are in-person assessments performed by a real estate agent. Unlike an online estimator which relies on an algorithm, a CMA is curated to your specific property. That matters because no two houses are exactly the same, so you need a person who is trained in home valuations to see your house in person to determine how much it is really worth.
Your realtor will handpick different properties that are most similar to yours, based not just on quantitative measures, but on qualitative measures that an algorithm can’t compute. For example, an agent will take into account whether your house has a desirable view or if it’s on a busy street — things that most algorithms struggle to put a dollar value on.
Plus, realtors are local experts — they know your neighborhood better than an algorithm ever can, so they know the nuances of what buyers are looking for.
For example, we talked to Steven Nicastro, a real estate agent in Charleston, SC, who was able to point out homes he personally knew had suffered from recent flood damage. Because algorithms aren’t always aware of flood damage, these properties can skew an online home value estimate.
Local knowledge is difficult for an algorithm to compete with. Your realtor will use houses that are far more comparable to yours — and therefore get you a more accurate home value estimate than an algorithm ever could.
Realtors also have access to the multiple listing service, which includes photographs and detailed information about real estate transactions. Using the MLS, your realtor can see photos of comparable properties to get a better idea of their condition, which an algorithm can’t really measure, but which makes a huge difference in the list price.
Realtors can see if other home sales included buyer concessions, which might result in a different sale price than what you could get for your property. Again, an algorithm will struggle to account for this kind of information — and it’s why CMAs are almost always more accurate.
Should I use a home value estimator to buy an investment property?
You definitely do not want to make any decisions about whether or not to buy an investment property based on what a home value estimator says. Home value estimators have wide margins of error — often between 2–7% — that can translate into tens of thousands of dollars.
When you’re investing, you’re looking at getting a deal. So the risk of a home value estimator overestimating what a property is worth could translate into you making less than what you expected — or even losing money on a property.
Instead, only use home value estimators to explore potential properties that you may want to invest in. There’s no harm in getting a ballpark figure from them to find out what a potential investment property may be worth.
But before making an actual offer on a property, you need to get a much more accurate value estimate through a comparative market analysis. If you’re an experienced investor, you may be able to run your own CMA.
But for all other investors, you’ll want to turn to a real estate agent. They’ll always be able to provide a much more accurate estimate of a home’s worth than an online home value estimator will.
Should I use a home value estimator when buying a home?
Home value estimators are primarily for sellers, but if you’re a buyer, you might get some use out of them as well. For example, you may want to compare the list price of a home with what a home value estimator says it’s worth.
If the home value estimator says that the home is worth a lot less than the list price, you might be able to negotiate more aggressively with the sellers. Pricing errors are especially common with for-sale-by-owner homes, so a home value estimator can alert you if a list price is potentially way off.
But don’t rely too much on a home value estimator when making an offer. Even if a home value estimator claims that a house is worth less than what it’s listed as, chances are that the estimator is wrong — not the list price.
A house listed with an agent will have had a CMA done, which is far more accurate than a home value estimator. Agents know this and they’re not going to be swayed by buyers trying to get a lower price because of what an online calculator says.
How are home values determined?
Determining home values is both an art and a science. When your real estate agent comes up with a comparative market analysis (CMA), they mainly rely on what are called “comps.” These are houses that have sold near your house that are comparable to yours.
Because your agent has access to the multiple listing service (MLS), they can pull up a trove of sales data going back decades and find comps that match your house in terms of things like:
- Square footage
- Recent renovations
- Access to schools
Your agent can also see pictures of homes that are for sale or have sold in the past. These pictures give your agent a much better idea of the condition of the home, which is something that makes a huge difference in terms of list price. Algorithms struggle with determining the condition of a home, which is a big reason why they’re often off by large margins.
Plus, agents have access to highly detailed information about previous housing sales, such as whether other houses in your neighborhood included buyer concessions and closing costs, which can have a big impact on the final sale price.
Should I use a home value estimator when refinancing?
No. Just like with a mortgage, refinancing requires you to get an appraisal to ensure that the loaned amount lines up with what your house is actually worth. A home value estimator is too unreliable for any lender to take seriously.
Because an appraisal is done in-person, the appraiser has a better idea of the condition of your home than a home estimator does. That can mean the appraised value of your home — and therefore what you can refinance it for — may be far from what an online home value estimator says.
But a home value estimator can give you a ballpark estimate of how much you may be able to refinance for — just don’t be surprised if that estimate ends up being far from what a bank will actually lend you.
Should I get an appraisal before I list my home?
Probably not. Appraisals are mostly for mortgage lenders. They don’t have much to do with getting you the best list price for your home.
In most cases, an appraisal is done after a buyer has already made an offer on your home. The mortgage lender typically requests one to ensure that the property isn’t overpriced and that the lender is giving a fair amount for the mortgage. So the appraisal is more about protecting the lender’s interests, not yours.
Unlike a lender, your real estate agent is approaching your home value as a marketing opportunity. They’re looking to land you a sale price that is both relatively high and likely to attract offers from buyers.
How should I estimate home value after renovation?
When calculating after renovation value (ARV), assuming a 70% return on investment (ROI) is a common rule of thumb.
Calculate ARV of your home using this formula:
ARV = current estimated home value + (70% × cost of renovations)
While you can use the 70% rule as a starting point to decide whether to take on a renovation project, don’t rely on it too much. It’s not very precise and certain renovations have a greater ROI than others.
Ultimately, you’re still going to need a real estate agent to provide a more accurate home value estimate with a comparative market analysis.
How can I increase home value?
Renovations that increase the value of your home the most include kitchen and bath remodels, window replacements, and a new roof.
However, while each of these projects will typically add tens of thousands of dollars to your home’s value, they are also major undertakings, both in terms of time and cost.
Simpler projects, like a garage door replacement or fresh coat of paint, are a lot less costly, but have a high return on investment.
Before undertaking any renovation project in order to increase your home’s value, consider your current market conditions and your timeline for selling. If you live in a hot seller’s market where your house is likely to sell quickly and over asking anyway, renovations may not make much of a difference in terms of attracting buyers.
But if you live in a slower market, then a remodeled home can help yours stand out from the rest and potentially get you more offers.
What is the assessed value of a home?
Assessed value is the value assigned to your property by a government assessor in order to calculate your property tax obligations. It is different from — and often lower than — your home’s fair market value, which is what your house could sell for on the market. That’s why you shouldn’t use your home’s assessed value to determine a listing price.
Assessed value differs by tax districts, but usually it is based on your home’s condition, size, and features, as well as current local property values. In some areas, the assessed value is a percentage of the fair market value.
Why do different home value estimators give different estimates?
Each home value estimator uses its own algorithm to decide how much a home is actually worth. These algorithms weigh different aspects of a property differently, which results in different home values.
For example, one home value estimator may place more weight on a renovated kitchen than another one. Or one estimator may only use sales data going back one year, while another uses sales data going back two years.
These differences begin to snowball, resulting in differences in home value estimates that can run in the tens or even hundreds of thousands of dollars.
Why doesn’t my home have a Zestimate?
Sometimes Zillow — and other home value websites — just doesn’t have enough data about a property to estimate its value. This may happen for a number of reasons.
For example, if you live in a non-disclosure state where real estate transactions aren’t publicly reported, Zillow may not have access to enough information about your home to make a Zestimate.
The other potential issue is if there aren’t enough real estate transactions in your county or ZIP code. Zestimates are based on what similar properties to yours have sold for in your area, so without that data an online home value estimate is nearly impossible. This is more likely to happen to you if you live in a rural area.
Why trust us?
Michael Warford has been writing about real estate for over a decade. He specializes in agent matching services, for-sale-by-owner services, and discount brokers.
This guide draws on hundreds of hours of research done by Michael and the team at Real Estate Witch. We tested dozens of home value estimators using test properties across the country to find the ones that provide the best value for you — and to eliminate those that didn’t make the cut.
Michael also drew on our in-house experts, including:
- Ben Mizes, investor and Clever Real Estate Co-founder: Ben has a portfolio of 22 properties in St. Louis, is a licensed real estate agent in Missouri, and helped grow Clever to one of the nation’s leading real estate education platforms.
- Steven Nicastro, investor and realtor: Steve closed $6 million in real estate transactions in the challenging Charleston, S.C. market in 2020 and 2021. He has also written for NerdWallet, the New York Times, USA Today, the Associated Press, and U.S. News.
- Trent Seigfried, data analyst: Trent works at identifying patterns in large data sets in the real estate industry and is the founder of a number of personal finance websites.
We considered several factors when assigning a grade to each home value estimator — most importantly, the error rates and geographical coverage. Because only half of the home value estimators publish their error rates, we lowered the scores of those that did not.
We also considered factors that didn’t have a direct impact on the accuracy of the estimators but could affect the user’s experience. For example, if a home value estimator required users to submit contact information and then used that contact information to spam them, we marked it down.