Estimate or Zestimate? Which is more accurate
Like Quint said in Jaws, "Y’all know me, know how I earn a livin’." We know that you know how us Realtors earn a livin'. However, in recent years, the idea of reaching out to a local Realtor for estimates or a market analysis has become taboo. “Why reach out when I can do it all online with Zillow?” It’s a valid argument, and we understand the ease of it—we don’t like it, but we get it. But how accurate is it, really? Are you getting accurate information?
First and foremost, what is Zillow? I’m sure most of you reading this know exactly what Zillow is and have used it more than a few times. But what do you know about them? Founded in 2006, Zillow Group, Inc. is the largest real estate marketplace in the United States. The purpose and design of Zillow is to help guide consumers through every stage of the real estate cycle. This includes buying, selling, renting, and financing—in basic terms, everything you need in one place.
Zillow offers a wealth of real estate information and services at your fingertips by offering the following:
Core Data & Valuation
Zillow aggregates listings for millions of properties across the U.S., including homes for sale (by agents and owners), new construction, foreclosures, and rentals.
Zestimate: This is perhaps Zillow's most famous feature—an automated valuation model that provides an estimated market value for approximately 104 million homes, whether they are on the market or not.
Buying & Selling Tools
It connects homebuyers and sellers with local real estate agents who pay Zillow for advertising and leads.
3D Home Tours & Floor Plans: Offers immersive digital experiences to help shoppers visualize homes remotely.
Seller Options: Provides sellers with various paths, including connecting with an agent or requesting a cash offer from partners like Opendoor.
Rental & Financial Services
The platform helps renters search, apply (using a universal application), and even pay rent online. It also provides landlords with tools for listing, screening tenants, and managing payments.
Zillow Home Loans: An affiliated lender that offers mortgage loans, refinance options, and pre-approvals to facilitate the home-buying transaction directly.
BuyAbility Tool: Helps buyers understand what they can afford based on real-time mortgage rates and personalized financial information.
Zillow's Resources for Real Estate Professionals
Zillow also offers great resources to real estate professionals as well by operating a two-sided marketplace:
Consumer Side (Free): Zillow attracts a massive audience of buyers, sellers, and renters by offering free, valuable content like property listings, neighborhood data, and the Zestimate. This high volume of traffic is Zillow's main asset.
Professional Side (Monetized): Zillow generates the majority of its revenue by charging real estate professionals for access to this large consumer audience:
Premier Agent Program: Agents pay for advertising and lead generation, gaining prominent placement on listings within specific ZIP codes.
Rentals & Landlord Services: Landlords and property managers pay for premium listing placement and tools like tenant screening.
Mortgage Origination: Income generated through loan origination fees and interest from Zillow Home Loans.
While the Zestimate is an excellent starting point, the Realtor's estimate is a more reliable measure of a home's actual market value.
CMA (Realtor) vs. Zestimate (Zillow)
The difference in accuracy comes down to the data source and the human element.
1. The Realtor's Comparative Market Analysis (CMA)
A CMA is a detailed report prepared by a licensed local real estate agent. It is a more accurate valuation because it includes the "art" as well as the "science" of pricing.
Key Factor | Realtor's CMA | Why It's More Accurate |
Data Source | MLS (Multiple Listing Service) Data: Realtors use official, verified, and recent sales data from the local MLS, which is often more comprehensive and up-to-date than public records. | They see the exact final sale price, not just the list price, and can access all relevant property details. |
Property Condition | In-Person Inspection: The agent physically walks through the home. | They factor in the condition (e.g., new roof, needed repairs), quality of finishes (e.g., custom cabinets vs. builder-grade), and curb appeal, which the Zestimate algorithm cannot see. |
Local Nuance | Neighborhood Expertise: Agents know hyper-local factors like which specific street or side of the street commands a premium (e.g., "The homes on the park side sell for 10% more"). | They can exclude irrelevant "comps" (comparable sales) that an algorithm might include, such as a foreclosure or a sale from a different, less desirable school district. |
Market Timing | Real-Time Market Pulse: Agents know how quickly the market is accelerating or decelerating and can factor in current buyer demand, inventory levels, and interest rate impacts. | They don't rely solely on lagging historical data; they price for the current reality. |
2. The Zillow Zestimate
The Zestimate is generated by an Automated Valuation Model (AVM)—a proprietary computer algorithm. It's fast and covers millions of homes but is limited by its inability to perform an in-person inspection.
Key Factor | Zillow Zestimate | Why It's Less Accurate |
Data Source | Public records (tax assessments, deed transfers) and user-submitted data. | Public data can be outdated (not reflecting a recent renovation) or simply incorrect (wrong number of bathrooms/square footage). |
Property Condition | None: The algorithm cannot assess interior condition or quality. | A newly remodeled luxury home is treated similarly to an identical home that hasn't been updated in 30 years, resulting in a significant under- or over-valuation. |
Local Nuance | Limited to ZIP code or wide geographical area. | It struggles with unique homes, rural areas with few sales, or markets where value changes dramatically between adjacent streets. |
Median Error Rate | Significant: Zillow publishes its median error rate, which is about 7.0% nationwide for off-market homes (homes not currently for sale). |
What does it all mean?
Here’s an example. You’re a lyricist; you’ve been writing and singing music for years and have had great success, moderate success, or no success, but have enough of a library to prove that you’re good at what you do. You write words and think about, "How well will this sing? Should I rephrase this sentence? Use a different word? Or maybe even use what would be considered poor grammar?" This is something that writers, singers, and artists in general do every day. They question what is considered "correct" and ask, "Is it an accurate portrayal?"
The same applies here with the difference between a CMA and an AVM. The AVM (Zestimate) provides a raw, quantitative answer based purely on data the computer can access. The CMA, however, is a valuation based not just on the data, but on a professional's experience, insight, and the human element—the same way a seasoned lyricist understands how to make words resonate.
Trust us to help you!
We here at Dutchess Country Realty recommend that you use every tool you have to help you get the best results in your real estate transaction. That being said, local agents have a wealth of knowledge that you can’t find on Zillow alone. Using a real estate professional that you trust to guide you through the process will always benefit you in the end.
If you or anyone you know is in the market to buy, sell, or rent a home, you can contact us at (518) 789-6184 or email Brad or Adam to help you with their wealth of knowledge.
