If you’ve ever typed your address into Zillow, Realtor.com, or another online estimator, you’ve probably seen a number pop up that looks surprisingly confident. Clean. Precise. Exact. The problem? That number often has very little to do with what your home would actually sell for.
Online valuation models (commonly called AVMs) rely on algorithms — not inspections. They pull public data, recent sales, and averages, then fill in the blanks. That can work sometimes in cookie-cutter neighborhoods, but it falls apart quickly in real-world scenarios.
Here’s what online estimates typically don’t see:
Interior condition and level of updates
Finished basements (or poor-quality finishes)
Functional layout issues
Deferred maintenance or hidden damage
Location nuisances like traffic, rail lines, or adjacent uses
Unique features that don’t fit an algorithm
Two homes with the same square footage and bedroom count can be tens of thousands of dollars apart once you step inside them. Algorithms can’t walk your property. Appraisers can.
Another big issue? Lag time. Online estimates often trail the market. In fast-moving or declining markets, those numbers may be based on sales from months ago — which means they’re already outdated.
This matters more than most people realize. Relying on an inflated online value can lead to:
Overpricing a home and sitting on the market
Underpricing and leaving money on the table
Poor financial decisions during divorce, estate planning, or refinancing
A professional appraisal doesn’t guess. It measures, inspects, analyzes, and explains. The result is a defensible opinion of value — not a marketing estimate designed for clicks.
If you’re making a decision that actually matters, an algorithm isn’t enough.