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Online estimates, and what they can’t see
An online home value estimate is a formula run over public records and recent sales. It’s quick and free, and it can’t see your kitchen, your permits or your street. Below, a live read of one city’s recent sales shows how wide the price per square foot runs: the range a formula has to guess within.
How they workLive price spreadWhere data runs thinHow to use one
- walks through your homeNevera formula works from records
- fewest sales we track104Monte Sereno, Jan 2024–Sep 2026
- most sales we track15,337San Jose, same 33 months
- silicon valley sales42,103same window, Santa Clara and San Mateo counties
how they work
How an online estimate works
An automated valuation model (AVM) takes the facts on record for your home and the recent sales around it, and fits a price. It learns from the data it has, and it can only be as close as that data.
What it sees
- Facts on recordSquare footage, bedrooms, bathrooms, lot size and year built, as the county or a listing reported them.
- Nearby salesRecent closed sales and their prices, weighted by distance and similarity.
- Listing historyPast list prices, price changes and days on market.
- Tax recordsAssessed value and past sale prices.
What it misses
- Condition and updatesA remodeled kitchen and an original one look the same on record.
- Work not on recordAdditions, conversions and remodels the county record doesn’t show.
- Layout, light and the streetHow the home lives, what it looks at and how its street trades.
- What hasn’t reached the MLSCompass Private Exclusives, homes about to list, and how buyers are reacting to what’s for sale.
live price spread
How wide one city’s prices run, live
Pick a city and a home type, and enter a size. We read the last 180 days of closed sales from the MLS and show the spread in price per square foot, then what that spread means for a home your size.
Price per square foot, last 180 days
thin data
Where the data runs thin
A formula needs sales to learn from. Some cities we cover close thousands of sales a year; some close a few a month, and those few can be very different homes.
| Area | Sales, Jan 2024 – Sep 2026 | Sales a month |
|---|---|---|
| Monte Sereno | 104 | 3.2 |
| Woodside | 192 | 5.8 |
| Portola Valley | 197 | 6.0 |
| Atherton | 201 | 6.1 |
| Los Altos Hills | 240 | 7.3 |
| East Palo Alto | 247 | 7.5 |
| Hillsborough | 306 | 9.3 |
| Millbrae | 396 | 12.0 |
| San Jose | 15,337 | 465 |
| Silicon Valley | 42,103 | 1,276 |
Closed sales of houses, condos and townhomes reported to the MLS, January 2024 – September 2026 (33 months), repeat records removed. The eight cities we cover with the fewest sales, then San Jose and Silicon Valley for scale.
how to use one
How to use an online estimate
- As a starting pointNot as a list price or an offer. It tells you roughly where to look.
- Check the facts it usesSquare footage, bedrooms, bathrooms and lot size. A wrong fact on record moves every estimate built on it.
- Compare a few, then compare with salesWhen estimates disagree by a lot, the data is thin or the home is unusual.
- Run the Comps FinderThe eight closest sales to your home from the last 180 days, adjusted to your size and lot.
- Ask for a walk-throughThe things a formula can’t see are the ones that move the price most from home to home.
go deeper
Every way we value a home
live toolfor owners
Comps Finder
The eight closest sales to your home from the last 180 days, each adjusted to your size and lot, plus what’s for sale near it now.
live toolfor owners
Home Equity Check
Your purchase price at your city’s pace, minus what you owe, with what selling would cost and how much of the gain is taxed.
guidevaluation 101
Home Valuation
Five values for one home: market, list, appraised, assessed and the online estimate.
guidesellers and buyers
Comparative Market Analysis
How comps are picked and adjusted, with an example grid you can check line by line.
guidebuyers and sellers
Home Appraisal
How the appraisal works, what a gap costs and how often homes here sell over asking.
guideproperty nerds
The Three Approaches to Value
Sales comparison, cost and income: how appraisers value property, with calculators.
questions
Questions we hear
How accurate are online home value estimates?
It depends on how much sales data there is and how typical the home is. A city with thousands of similar sales a year gives a formula more to learn from than a town with a few sales a month. The live tool above shows how wide one city’s price per square foot runs.
Why do different websites show different values?
Each runs its own formula over its own data, and each updates on its own schedule.
Why did my estimate change when nothing changed at my home?
Nearby sales closed, a listing changed, or the model was updated.
Can I correct my home’s facts?
Many sites let owners update facts such as bedrooms and remodels. The county record is the source many start from, so check it too.
Is an online estimate the same as a CMA?
No. A CMA is prepared by an agent who picks and adjusts the comparable sales and usually sees the home. An online estimate is a formula that does neither.
What estimate do you give?
Our home value page gives an instant estimate, and then a Property Nerd checks it against your street, your home and the sales a buyer would compare it with.
more to learn
Keep going
- What’s my home worth?An instant estimate, then a Property Nerd checks it against your street.
- Comps FinderThe eight closest sales to your home from the last 180 days, adjusted to your size and lot, live.
- Home Equity CheckYour purchase price at your city’s pace, minus what you owe, with what selling would cost.
- Home ValuationMarket, list, appraised, assessed and online values: who sets each and which one matters when.
- Comparative Market AnalysisHow an agent picks comps, adjusts them and turns them into a price range.
- Home AppraisalHow the appraisal works, what a gap costs and how often homes here sell over asking.
- The Three Approaches to ValueSales comparison, cost and income, with calculators for the last two.
- Then & Now CalculatorWhat a price from any year since 2012 is worth now, by city.
- How Much Over AskingThe Silicon Valley overbid in dollars, by year, city and price band.
- Price per Sq Ft MapMedian price per square foot by neighborhood across Silicon Valley.
Estimates and examples for discussion only; not an appraisal, and not tax, legal or lending advice. Sales data: MLS via IDX, deemed reliable but not guaranteed. Equal Housing Opportunity.
talk to a property nerd
Want a number from someone who’s seen it?
We’ll walk through your home, pull the closest sales and give you a price range you can plan around. Commissions are negotiable, and we offer bundled services, so ask us what’s included.
Eric & Janelle Boyenga
Realtors DRE01254724 / 01254725
Realtors DRE01254724 / 01254725