Type your address into a few of these sites and you’ll get three or four different numbers, sometimes tens of thousands of dollars apart. That’s confusing, but it’s not because one of them is wrong exactly. They’re just built differently.
All of these tools are what’s called an automated valuation model. They pull public records, recent sales, and basic details like square footage and bedrooms, then run that through an algorithm to land on a number. None of them have actually walked through your house.
Redfin’s estimator tends to be the most accurate for homes currently listed for sale, with a median error rate under 2 percent, because it updates directly off MLS data, often daily.
Zillow’s Zestimate is the one most people have actually used. It’s the most visited tool out there and covers a huge share of homes nationwide. It runs a bit less precise than Redfin for active listings, with a median error closer to 3 percent, but it tends to hold up about as well for homes that aren’t currently for sale.
Realtor.com blends data from a few different sources to land on its number, which can make it a reasonable ballpark, though it doesn’t publish how accurate it actually is, so it’s harder to know how much to trust it.
Estimators from banks like Chase or Bank of America are the least reliable of the group. They’re built mainly to support refinancing, and they’ve been shown to come in tens of thousands of dollars under other tools, so I wouldn’t lean on one of those to set expectations for a sale.
Even the best of these tools can be off by 5 to 7 percent, which on a $400,000 home is a $20,000 to $28,000 swing. They don’t know if you replaced the roof last year or if the basement still has the same carpet from 1995.
That gap matters more in a market like Ann Arbor or Ypsilanti, where comparable homes a few blocks apart can sell for noticeably different prices depending on updates, lot size, and timing.
These tools are a fine starting point if you’re just curious. When the number actually matters for a real decision, it’s worth getting a comparison based on actual nearby sales and the specifics of your home. I’m happy to put one together for you, no pressure either way.
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