How Accurate Is a Zestimate on a Shore House? Zillow’s Own Numbers

Zillow publishes how often its own Zestimate misses. It's on their website, state by state.

For New Jersey homes that weren't for sale, the median miss is 7.36%. That sounds small. It isn't. A median means half of those estimates missed the actual sale price by more than 7.36%, and on a Shore House, 7.36% is real money.

How accurate is a Zestimate in New Jersey?

For a home that isn't on the market, Zillow's own figure for New Jersey is a 7.36% median error. Only 61.8% of those estimates landed within 10% of what the home actually sold for. That leaves about 38% that missed by more than 10%, and about 15% that missed by more than 20%.

The national number is almost the same, a 7.20% median miss. New Jersey isn't an outlier.

Read the 38% again.

Why is the Zestimate closer on homes that are listed for sale?

Once a New Jersey home is listed, the median miss drops to 2.10%. That's not a surprise. Once a home is for sale, Zillow adds the asking price, the listing description and days on market to the model.

By then the seller and their agent have already done the hard part. They priced it against the competition and the recent sales. The estimate gets to lean on that work.

When you look up your own house, it's not on the market. The 7.36% is the number that applies to you.

What does a 7.36% miss look like on a Shore House?

In 9 of the 12 island towns from Brigantine to Cape May Point, the median sale price over the last 12 months was over $1 million. On a $1 million house, a 7.36% miss is about $74,000. A 10% miss is $100,000.

Here's what New Jersey's median error works out to at each town's median sale price.

Put your own number in.

Why do automated values miss at the shore?

Zillow says its model runs the same way on every home, using standard data like bed and bath counts, square footage, lot size, tax assessments and prior sales. That works well in a subdivision where the houses look alike and size is most of the story.

On the islands it isn't.

Price per square foot is not a useful way to value an island property. One block, even half a block, closer to the beach moves the value more than the square footage does. A bayfront lot with a dock. An ocean view from the top floor. A quiet block versus a house on a main road. None of that shows up in a bed and bath count, and a water view isn't on Zillow's list of standardized data.

Condition is the other blind spot. Zillow's own page says additions and remodels that were never reported don't show up in the Zestimate, and cosmetic updates may not move it at all. A condo owner who asked me for a value this month rated her unit a 10 out of 10, fully redone by a designer. Zillow can't see inside your house or condo, so how would it adjust the value for that? If the work never made it into the public record, the estimate is valuing the unit as it looked before.

Did Zillow's own CEO get a bad Zestimate?

He did. In February 2016, Spencer Rascoff, Zillow's CEO at the time, sold his Seattle home for $1.05 million. The day after the sale, its Zestimate was about $1.75 million. That's roughly 40% higher than what it actually sold for.

Zillow's explanation at the time is the interesting part. The house sat on an odd triangular lot, and the model was comparing it to sales on normal rectangular lots. It was also on a busy road the comparable sales weren't on. One of their economists called it "the classic luxury homes problem," since the estimate can't account for things like layout or lighting.

That was 10 years ago, and Zillow has rebuilt the model since. But read those reasons again. The lot, where it sits on the block, and what's inside. Those are the same things that drive value on the islands.

In my professional opinion, this is where automated values break down on the islands.

How do you get an accurate value on a Shore House?

Start with what you'd be competing against today and what recently sold that's actually comparable. Same island, same distance to the beach or bay, similar condition. Then adjust for what the records don't show: the view, the renovation, the lot.

Properties are valued by what's available (the competition) and what recently sold. Not by a model's average. Even Zillow says to supplement the Zestimate with an appraisal or a comparative market analysis from a real estate agent.

Once you have a number, how you price it matters just as much. More on that in why pricing a Shore House too high costs you money. For current sales and inventory by town, the live market dashboard updates every morning.

Common Questions About Zestimate Accuracy

How accurate is a Zestimate for a home that isn't for sale?

In New Jersey, Zillow's own median error for off-market homes is 7.36%, and about 38% of estimates miss the sale price by more than 10%.

Why is my Zestimate closer once my house is listed?

Once a home is for sale, Zillow uses the asking price, the description and days on market. In New Jersey the median miss on listed homes is 2.10%.

Does the Zestimate count a renovation?

Only if it's reported. Zillow says unreported additions, updates and remodels aren't reflected, and cosmetic updates may not change the estimate.

Is a Zestimate an appraisal?

No. Zillow says the Zestimate is not an appraisal and can't be used in place of one.

Does Zillow publish accuracy for the Jersey Shore?

No. Its tables go down to the state and large metro areas. The closest figures are New Jersey at 7.36% and the Philadelphia metro at 7.65%, both for off-market homes.

The Bottom Line

Zillow is upfront about it. For a New Jersey home that isn't for sale, half its estimates miss by more than 7.36%, and close to 4 in 10 miss by more than 10%. At island prices that's often a six-figure gap.

What your Shore House would actually sell for comes from today's competition and real comps on your part of the island. If you'd like that done for your property, reach out here.