Can You Trust the Zillow or Redfin Estimate on Your Eastside Home? What the Numbers Really Say

Almost every seller I meet has already looked up their home online. Someone types in an address, a number pops up, and a few minutes later that number has become the starting point for the whole conversation. So let's talk plainly about where those numbers come from, what the companies say about their own accuracy, and how to use an estimate without letting it steer your plans.

How Automated Home Value Models Work

Zillow's Zestimate and the Redfin Estimate are what the industry calls automated valuation models, or AVMs. Nobody walks through your house. Software compares your address and its recorded details against nearby sales and public data, then produces a number.

Zillow describes the Zestimate as the output of a neural network-based model that draws on county and tax assessor records and direct feeds from multiple listing services. Inputs include square footage, location, bedrooms and bathrooms, and, for homes on the market, the list price, description and days on market. Redfin says its estimate uses MLS data on recently sold homes and weighs hundreds of data points about the market, the neighborhood and the home itself, including things like a water view or a busy street.

Both companies are upfront about the limits. Zillow's page states that the Zestimate is not an appraisal and can't be used in place of one. Redfin calls its estimate a starting point and not a formal appraisal.

What the Companies Publish About Their Own Error Rates

I pulled the published figures today. They are national numbers, and the companies refresh them on a schedule, so they will change.

• Zillow: The Zestimate accuracy page (last refreshed November 2, 2026) shows a nationwide median error of 7.21% for off-market homes. For on-market homes, the page showed "NA" when I checked, so I can't quote an on-market figure from Zillow's own table. The Seattle row on that page also showed "NA", and I did not see Bellevue, Kirkland, Redmond or Sammamish listed.
• Redfin: The Redfin Estimate page (updated October 25, 2026) shows a median error of 1.91% for homes listed for sale and 7.50% for off-market homes. About 93% of on-market estimates landed within 10% of the sale price, compared with about 60% of off-market estimates. About 82% of off-market estimates landed within 20%.

Here is what "median error" means. If the median error is 7.5%, then half of the estimates were closer to the final sale price than that, and half were farther away. It tells you nothing about how far off the worst misses were. Redfin's own table shows that roughly one in five off-market estimates missed by more than 20%.

Notice also why the on-market numbers look so much better. When a home is listed, the model gets the asking price, the listing description, photos and real buyer activity. That is far more information than it has for a home that is not for sale, which is the situation most people are in when they check their own value.

What 7.5% Looks Like in Dollars

A percentage can feel abstract, so here is a simple illustration. On a $1,400,000 Eastside home, a 7.5% miss is $105,000. A 20% miss is $280,000. These are examples of the math, not predictions for any particular house. The point is that on higher-priced homes, even a "typical" error is a number that matters when you are deciding whether to sell, what to list for, or how much equity you have.

Why Eastside Homes Are Harder to Estimate

An algorithm does best with homes that look alike: a subdivision of similar floor plans, built in the same few years, on similar lots. Plenty of Eastside homes don't fit that mold. Here are the features that tend to trip up an automated model:

• Recent remodels. Both companies note that work not captured in public records or MLS data may not show up in the estimate. A kitchen and primary bath redone last year can be invisible to the model. Zillow suggests reporting additions and remodels to your county assessor and updating your home facts on its site.
• View and lot differences. Two houses on the same street can sit in very different situations: a territorial view of the lake or mountains, a flat usable yard, a steep slope, a greenbelt behind the fence, or a busy road out front. Redfin lists a water view and a busy street as examples of what its model looks at, but a model can only guess at how a particular view or lot actually feels and shows.
• Unusual or custom homes. One-of-a-kind floor plans, major additions, an accessory dwelling unit, or a home with a lot of square footage that is unfinished or unpermitted can be hard to compare to a standard sale.
• Condition and finishes. Original everything and fully updated can look identical in a database. Buyers see the difference in the first thirty seconds.
• Fast-moving or thin markets. If only a few comparable homes have sold nearby recently, there is less for the model to work with, and prices can shift between the date of a sale and the date of your estimate.

What a CMA and an Appraisal Do Differently

These three tools answer slightly different questions, and it helps to keep them straight.

A CMA, or comparative market analysis, is what I prepare for a seller. I walk through your home, note the condition, updates, floor plan, view and lot, then compare it to recent sales, pending sales and active listings that a buyer would actually weigh against yours. Because I can see things a database can't, I can explain why one comparable is more relevant than another and where your home might sit in a range. A CMA is an opinion of likely market value for the purpose of pricing a listing. It is not an appraisal.

An appraisal is done by a licensed appraiser, usually ordered through a lender when a buyer is financing a purchase or when a homeowner is refinancing. The appraiser inspects the property and writes a formal report following professional standards. This is the number a lender relies on, which is why Zillow itself says a Zestimate can't be used in place of one.

An AVM estimate is software output. It is fast, free and useful for a quick look, but it doesn't have eyes on your home.

How to Use an Online Estimate as a Rough Starting Point

I'm not telling you to ignore these tools. I use them too, mostly to see how a home's public record looks to buyers. Here is how I'd suggest using them:

• Treat the number as a range, not a price. If Zillow shows one figure and Redfin shows another, the gap between them is itself a reminder of the uncertainty.
• Check the facts behind the estimate. Look at the square footage, bedroom and bathroom count, lot size and year built the sites have on file. If something is wrong, request a correction. Make sure your remodel history is on record with the county.
• Look at the comparables yourself. Redfin and Zillow both show nearby recent sales. Ask whether those homes really match yours in size, condition, view and street.
• Don't anchor on a high number, or panic over a low one. An estimate that is above what the market will pay can lead to a listing that sits. One that is below can lead you to underprice a home that has real advantages.
• Never use it to set your list price. The market sets the price, and a home-specific analysis is far better placed to read it.
• Don't use it to decide a purchase either. If you are buying, a lender's appraisal and the comparable sales matter more than any website estimate.

A Practical Next Step

If you are thinking about selling in the next year, or you just want to know where your home really stands, the most useful thing is a conversation about your specific house. I can look at what you have updated, how your lot and view compare to recent sales, and what buyers in your part of the Eastside are responding to right now. There is no obligation, and I'll tell you honestly where I think an online estimate is close and where it may be missing something.

Reach out anytime to set up a quick call.

This post is general information for educational purposes and is not legal, tax or financial advice. Accuracy figures are national numbers published by the companies, checked on November 4, 2026, and they change over time. Dollar examples are illustrations, not valuations of any specific home. Sources: Zillow Zestimate accuracy page (zillow.com/zestimate, refreshed November 2, 2026); Redfin Estimate accuracy page (redfin.com/redfin-estimate, updated October 25, 2026).