Dear Dave,

We’re thinking about selling our house, but first, we want to know how much it’s worth. We’ve seen websites like Zillow and Trulia that offer home value estimates, but we’re not sure how reliable they are. When selling a home, how do you determine if these websites provide an accurate value?

— Tom, Grand Junction

Tom,

Great question! For this answer, I’ll focus mainly on Zillow, since it’s one of the most popular sites people turn to for home values and real estate trends. Zillow has done a fantastic job marketing itself as the go-to source for home value estimates with its “Zestimate.” However, it’s important to understand just how accurate—or inaccurate—that Zestimate really is.

If you visit Zillow’s FAQ section and look under “How accurate is the Zestimate?” you’ll see they openly admit their estimate is often not very precise. Despite the slick marketing, the Zestimate can be off more than it’s right because it relies on algorithms that can’t fully account for the many nuances of an individual home or neighborhood.

Why Zillow Estimates Can Miss the Mark

Zillow often cites its Zestimate accuracy as within 5, 10, or 20%, but remember, that means plus or minus. For example, in Colorado, if an off-market home (one not currently for sale) has a Zestimate of $450,000, the actual value could range anywhere from about $416,250 to $483,750—and that spread only covers the Zestimate’s accuracy about 46% of the time. The other 54% of the time, the estimate can be even further off. So, if your home isn’t on the market, Zillow’s estimate is essentially a rough guess.

What Happens When Your Home Is On the Market?

Interestingly, once a home is listed for sale—whether by an agent or owner—the Zestimate becomes more reliable. In Colorado, Zillow reports that about 95% of on-market homes have estimates within about 2.5% of the list price. Why the big jump? Because the listing price is set by a real estate professional with local market knowledge, which Zillow then factors into its algorithm. So, that “valuable signal” Zillow talks about is basically an expert’s pricing input, which improves the estimate’s accuracy.

So, Are These Online Estimates Worth Using?

I’d say these automated online valuation tools like Zillow are best used as a general starting point or a historical reference—not for accurately pricing your home. They can be helpful to get a rough idea of market trends or how your home compares to others, but they’re no substitute for a professional market analysis.

The best way to determine your home’s value is to have a knowledgeable local real estate agent—or even a few—come out, see your home, and provide a Comparative Market Analysis (CMA). This involves looking at recent sales of similar homes in your neighborhood and what buyers are actually paying, which tells you much more than any algorithm can.

As artificial intelligence and data analytics improve, these online tools may get better. But for now, the human element and local expertise remain the gold standard.

Hope this helps!

Dave Kimbrough – RE/MAX 4000
The Kimbrough Team
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