What's My Home Really Worth? The Problem with Zillow "Zestimates"

Susan Heckman
1 day ago
5 min read

I get this call more than almost any other.

A homeowner has been casually watching Zillow for a few months, maybe longer. They've seen their "Zestimate" climb, and now they're curious. They call me expecting I'll confirm the number on the screen, and we'll go from there.

Sometimes I do. More often, I don't.

And when I explain why, the conversation almost always leads somewhere really useful — a real picture of what their home is worth today, in this market, in their specific neighborhood. That's the number that matters. And it's rarely the one Zillow gave them.

What Is a Zestimate, Really?

Zillow's Zestimate is an automated estimate generated by an algorithm. It pulls from publicly available data: tax records, recent sale prices, square footage, lot size, number of bedrooms and bathrooms, and runs it through a formula to produce a dollar figure.

It's a useful starting point for casual browsing. It is not a home valuation for the serious seller, especially if you are a longtime homeowner.

Zillow actually publishes its own accuracy data, and it's worth knowing: nationally, Zillow reports a median error rate of around 2–3%, and that’s for homes that are currently listed on the market. But for homes that are off the market, which is every home until the moment it lists, that error rate jumps significantly. In some markets and some price ranges, Zestimates are off by 10%, 15%, or more in either direction.

In Monmouth and Ocean Counties, where neighborhoods can shift dramatically from one street to the next, that margin of error has real dollar consequences.

EXAMPLE:

For a home with a market value of $1,000,000, the Zillow Zestimate could miss the mark by $100,000-$150,000. This is significant!

What Zillow Can't See

Here's what the Zillow algorithm simply cannot account for:

Your home's condition. This is the most important factor, and is why an experienced agent is needed to determine your home’s true market value. Has the kitchen been fully renovated? Is the HVAC original to the house? Are there deferred maintenance issues a buyer's inspector will flag? Zillow has no idea. Two homes with identical square footage and bedroom counts will sell for very different prices depending on what's inside.

Your specific neighborhood dynamics. Not all of Spring Lake is the same. Not all of Middletown. Not all of Toms River. Proximity to the beach, school district grades, noise, traffic, lot characteristics, and even the feel of a particular block all affect value, none of which shows up in a tax record.

Upgrades and finishes. A finished basement, a new primary bath, a whole-house generator, an in-ground pool, a wraparound porch — these all add value, but Zillow doesn't know about them unless they're in the public record (and they usually aren't).

What's actively competing with your home right now. A home priced for the market today is competing against everything else currently available to buyers in your price range and area. That competitive landscape changes constantly. An algorithm looking backward at historical sales can't price you for what's in front of buyers today.

Buyer psychology in your specific market. In 2025, single-family homes in Monmouth County sold for an average of 101% of asking price in just 34 days. In Ocean County, homes moved at 99% of asking in 40 days. That tells you something an algorithm can't: when a home is priced correctly here, buyers compete for it. Knowing how to use that is a strategy, not a formula.

A Tale of Two Numbers

Let me give you a real-world example of how this plays out.

I recently prepared a Comparative Market Analysis for homeowners in Monmouth County. Their Zestimate had been hovering around a number they’d grown comfortable with. When I sat down with them and walked through the actual comparable sales, homes that had recently sold nearby, adjusted for condition, upgrades, and current market conditions, their home was worth meaningfully more than Zillow suggested.

They had invested significantly in the kitchen and both bathrooms over the past several years. They had a fenced yard with a pool in a desirable location. The home was meticulously maintained. None of that was captured in the Zestimate. But all of it matters to buyers, and to their final sale price.

On the flip side, I've also seen the reverse: homeowners who were planning to sell, glued to a Zestimate that had inflated during a hot market, surprised to learn that despite recent local sales in the area, their own home told a different story when factoring in an aging HVAC system and the busy road location. Going to market with an inflated price is one of the most costly mistakes a seller can make. Homes that start overpriced and then reduce often sit longer and ultimately sell for less than homes that were priced right from the start.

What a CMA Actually Is

A Comparative Market Analysis is not an algorithm. It's a professional evaluation prepared by a local Realtor who knows your market, your streets, your neighborhoods, and your buyers.

A thorough CMA includes:

Recent comparable sales — homes similar to yours that have sold within a meaningful timeframe and radius, adjusted for differences in size, condition, and features
Active competition — what's currently on the market and competing with your home for the same buyers
Pending and expired listings — what buyers passed on and why, which tells you where the ceiling is
Days on market trends — how quickly homes like yours are moving right now
Price per square foot analysis — calibrated to your9 neighborhood, not just your zip code
A professional assessment of your home's specific condition and features — the things Zillow can't see

The result is a pricing recommendation grounded in what's actually happening in your market today, not a national algorithm's best guess.

What This Means If You're Thinking About Selling

If you've been watching your Zestimate and wondering whether now is a good time to sell, here's the honest answer: the Zestimate is a reason to start the conversation, not to end it.

New Jersey continues to be one of the strongest real estate markets in the country — in early 2026, NJ ranked #1 nationally for home price growth, posting a 5.93% year-over-year increase. In Monmouth and Ocean Counties, prices have been climbing steadily for years while inventory continues to lag. And there is real equity to unlock in many of these homes.

The right asking price, grounded in a professional CMA, is what creates competition among buyers, keeps your home from sitting, and gets you to the closing table with the strongest possible result.

Let's Find Out What Your Home Is Actually Worth

I offer a complimentary, no-pressure Comparative Market Analysis for New Jersey homeowners. It takes about an hour of your time, and it gives you a clear, honest picture of what your home is worth in today's real life market, not Zillow's algorithm-generated market.

No obligation. No sales pitch. Just real information to help you make confident decisions about one of the biggest financial assets you own.

Visit my sellers info page to learn more, or reach out anytime for an informative consultation and complimentary Comparative Market Analysis.

Susan Heckman

Broker-Associate

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