What a free CMA actually tells you (and what Zestimate doesn't)

Every week a seller emails me a Zestimate and asks if it is right. Usually the answer is no — off by 8 to 15 percent on North Shore homes, sometimes worse on older houses or unusual lots. Zestimate is a blunt instrument trained on the whole country. A real CMA is a scalpel trained on your block.

What a CMA actually looks at

• Recent sales (closed, not listed) of comparable homes within 0.5 to 1 mile of your property, usually the last 3 to 6 months
• Square footage, bedroom/bathroom count, lot size, and year built — all matched within a realistic band, not just ranked
• Condition notes from listing photos and agent remarks (renovated kitchen, new roof, basement finish quality)
• Currently-under-contract homes to see what buyers are willing to pay right now
• Active listings at comparable price points to see the competition
• Market velocity: days on market, sale-to-list ratio, and whether homes in your range are selling with multiple offers

What Zestimate misses

Zestimate weights recent sales but ignores condition, weights square footage but not layout, and averages across zip codes that often contain very different sub-markets. On the North Shore, the east side of Green Bay Road is a fundamentally different market from the west side, and a Zestimate will not see that. Neither will an algorithm see that your kitchen was gutted in 2024 or that your basement floods in heavy rain.

How to read the CMA without getting sold

A CMA should give you a range, not a single number. Any agent who tells you your home is worth exactly $1,247,500 is selling you a listing, not an analysis. The honest answer is always a range — something like $1.15M to $1.25M, with the top of the range requiring specific prep (staging, touch-up paint, photography, and a weekend of open houses).

Ask to see the comps. Not just addresses — photos, square footage, sale date, sale price vs list price. If the agent can't walk you through each one, the CMA was done by software, not by a human who knows your market.

The worst thing a seller can do is list based on a Zestimate. The second worst is list based on an agent's inflated number designed to win the listing. A real CMA protects against both.