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How much is your home really worth? Home Estimation Website vs. Realtor

Most home searches begin online. Likewise, a lot of sellers begin calculating the sales price of their home by visiting Home Estimation Websites online. While these sites may offer a wealth of knowledge on particular properties, they are hardly accurate in determining home value. There are many different sites that will automatically calculate your home value for you, and if you plugged your home address into each of these sites, you would get a different value for each one.

There truly is value in utilizing the knowledge of a Realtor.

How a Realtor Determines Your Home's Worth

But How does a Realtor Determine Your Home’s Worth?

A Realtor uses specific techniques to calculate the list price (when working with sellers) or offer price (when working with buyers) of a home through the process of conducting a CMA (comparative market analysis). The CMA is based on a mixture of data, experience, and local market knowledge on which homes to use as comparisons.

  • Property visit: To determine the current worth of a home, a Realtor will visit the property first. This step is crucial in determining the home’s condition, location, unique features, amenities, and to analyze the area around the property, which all influences the value.
  • Records & research: To assess the property accurately, a Realtor will then pull tax records, and will look to see if the home was ever listed in the local MLS. They may even glance at these Home Valuation Websites for more information on the home. This information, along with the information they gathered from the walk through, will help determine the type and style of the home, how many bedrooms and bathrooms the home has, the square footage, the age of the home, the size of the lot, etc.
  • MLS comps: Once they have all this information figured out, a Realtor will begin looking at comps through the MLS. The key is to find comps that are most similar to the subject property, using the most current and relevant information.
    • Typically, a Realtor will want to stay within the same elementary school district, but if nothing is found there, they may go out to the middle or high school districts if needed.
    • A Realtor doesn’t like to go back more than 6 months when analyzing comps. The more recent the better!
    • A Realtor will look at homes currently listed, as well as homes that are pending (under contract) and recently closed homes. In some markets, they will even look at homes that were released, withdrawn, or expired in order to determine the price.
    • And finally, a Realtor will look at all the specific features of a home and find the most similar homes to compare to. In each case, they will add or subtract value for certain things such as garages, number of bedrooms and bathrooms, flooring type, granite countertops, etc.

A Realtor knows that in the end, the true value of a home is what a buyer will pay for it. So they want to make sure they have the best idea possible of how much a buyer will pay for the property in current market conditions to sell your home quickly and for the best possible price (or when representing the buyer, to make sure they are getting the best deal possible).

On top of that, the home must go through an appraisal once a buyer and seller come to an agreement in order for the bank to lend the buyer the money to purchase the home. So, it is very important to get the numbers as accurate as possible. While you may want to ask your Realtor to list higher, studies have shown that an overpriced home that stays on the market will end up selling for less than the estimated price the Realtor suggested. Not only will you get less money in the end, you will still be responsible for the mortgage and bills on the home until it sells.

How do Home Estimation Websites Determine Your Home’s Worth?

So, why did your Realtor tell you a certain price, but the estimates offered under home valuation websites differ drastically? This is partly because these sites gather their data from different sources. Some gather information directly from the MLS, some from broker websites, and some take from tax records. They use an automated valuation model (AVM) and each site’s model is pulling different comps, and different calculations in order to come up with their figures.

Zillow is one of the most popular home estimation websites, and if you visit their questions page at they tell you how they come up with their figures. They focus on physical attributes, tax assessments, prior and current transactions, price history, and tax history. Their price is affected by the amount of data they can collect. In fact, some areas will show no computation, because some states, such as Texas or Maine, do not allow public access to prices of homes that sell. On these, there will be no data, no error rate, and no valuations.

Zillow’s price is also affected by information that homeowners manually change themselves on the site. Sometimes people will change their information so much until they get the figure they want, to the point where it isn’t accurate information anymore. So keep that in mind.

Zillow will share that they are just a “starting point in figuring out the true value of a house,” and according to, the “Zestimate’s accuracy depends on location and availability of data in an area… the more data available, the more accurate the Zestimate value. You can go see the chart of accuracy for specific areas, and it shows a median error of 2.8–9%.”

And according to, Trulia’s median error is 5.3%, and is affected by availability of data from public records, from real estate agents, and other sources, from uniqueness of a property’s features, number of transactions in an area over a period of time, and speed in data being reported.

The main issue is that these sites have no way of knowing the condition of the home, if it is in poor condition or if it has just been remodeled. They also don’t take into account different architectural styles, layout of the home, area amenities and other custom features. These types of automated valuation methods ideally work best for cookie cutter homes in average condition.

While you may not receive accurate information from these websites, they will serve as great sources of information on your property.

But in the end, the only way to really know what your home is worth is to allow a Realtor to conduct a personalized CMA (comparative market analysis) by inspecting your property, and going through their steps to customize a price specific to your home.

Want more advice about all things home — including homebuying or selling advice? Nestiny is a great place for homebuyer education and to help you gauge how ready you are to buy a home. Journey Homeward allows you to enter all your wants and needs while the True Affordability Tool will break down your budget, showing what you can comfortably afford. You will also receive a Ready Report that will give you a vital head start in the home buying journey, saving you valuable time and money.

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