If you’ve ever looked up a home on Zillow, chances are you’ve seen the Zestimate — Zillow’s estimate of a home’s market value. But are Zillow Zestimates accurate? And should you trust them when buying or selling a home?

Let’s break down how Zestimates work, how reliable they are, and what you should consider when pricing your home.

What Is a Zestimate?

A Zestimate is Zillow’s estimated market value for a home, calculated using a proprietary algorithm that pulls from public data, MLS records, tax assessments, recent sales, and market trends. It updates regularly and is available for millions of homes across the U.S.

Zillow claims their Zestimates are within 2-7% of a home's actual sale price—but that margin of error can make a big difference, especially in hot or unique markets.

How Accurate Are Zestimates?

The short answer: Zestimates can be a helpful starting point, but they are not always accurate. Here’s why:

1. They Don't See Your Home

Zillow can’t account for renovations, upgrades, or damage unless it’s been reported. A newly remodeled kitchen or a finished basement could add thousands in value—but Zillow won’t know unless you tell them.

2. They Rely on Public Data

If tax records or MLS data are outdated or incomplete, the Zestimate will be off. In areas where homes are very similar, the Zestimate might be more reliable. But in areas with unique homes or low sales activity, accuracy drops.

3. They Can’t Replace a Local Expert

Zestimates use broad market trends. Real estate agents and appraisers provide pricing based on current, hyperlocal data and firsthand knowledge—something an algorithm can’t replicate.

Pros and Cons of Zillow Zestimates

Pros:

• A helpful starting point for home value research

• Free and easily accessible online

• Gives a rough snapshot of a property’s market range

Cons:

• Doesn’t reflect property condition or upgrades

• Can be significantly off in volatile or rural markets

• Not used by professionals for official valuations

What Should You Use Instead?

While it’s okay to check the Zestimate, it’s best to use it alongside:

• A Comparative Market Analysis (CMA) from a local agent

• A licensed appraisal if you're refinancing or need an official value

• Recent neighborhood sales of similar homes

These options give you a much more accurate and actionable idea of your home’s value.

Zillow Zestimates are a decent tool for general insight, but they should never be the only source you rely on. When it comes to buying or selling a home, it's always best to work with a local real estate expert who understands your specific market, your neighborhood, and your property’s unique features.

Thinking of selling your home? Let’s get a personalized market analysis that gives you a true picture of your home’s value—no guesswork needed!

Matt Witte strives to be the best realtor in Andover MA.

Any questions about real estate, reach out to Matt Witte Andover Realtor MA