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Single Family ResidenceResidential
$4,092,886$1,450 / ft²
TopHap EstimateOur estimate of what this home would sell for today, based on nearby sales, the home's size and features, and local price trends. It is a starting point, not an appraisal.· confidence 96How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Aug 30, 2026
Last sold for $1,575,000 on Feb 14, 2007

21663 CASTLETON ST

CUPERTINO, CA 95014
5
Beds
3
Baths
2,822 ft²
Living AreaTotal finished area of the structures, from county records. Some counties include shared space like hallways or a building gym, so it may not match a listing.
0.17 ac
Lot SizeThe size of the land the home sits on, from county records.
1966
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
10
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.
2
ParkingThe number of parking spaces on the property, including the garage.

Valuation

$4.1M
$3.9M low$4.2M high
Last SaleThe most recent sale price and date from the recorded deed. Transfers between family members or companies may not reflect market value.$1,575,000 · Feb 14, 2007

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$25,660 (2025)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$2,152,357 (2026)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$1,613,930
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$538,427
Previous AssessedThe county's assessed value from the year before, useful for seeing how the assessment changed.$2,110,155

Climate Risk

Overall riskThe average of the five hazard scores below, on a 0 to 100 scale. Higher means greater projected risk over the coming decades.43
35
FloodProjected flooding risk from rivers, heavy rain, and storm surge, scored 0 to 100. Higher is riskier.
61
WildfireProjected wildfire risk, scored 0 to 100, based on how much land burns in a typical year. Higher is riskier.
26
HeatProjected heat risk, scored 0 to 100, based on how many extremely hot days a year are expected. Higher is riskier.
48
StormProjected risk from heavy rainstorms, scored 0 to 100, based on how often extreme rainfall is expected. Higher is riskier.
47
DroughtProjected water shortage risk, scored 0 to 100. Higher means more strain on the local water supply.
Projected Flood DepthHow deep a serious flood is expected to get here at some point in the next 30 years. Shown in inches.29 in
30-Year Flood ChanceThe chance of at least one serious flood here in the next 30 years, not in any single year.6%
FEMA Flood ZoneFEMA's flood zone for this address. Zones starting with A or V are high risk, and lenders usually require flood insurance there.1 percent flood zone

Scores 0–100; higher = greater projected risk.

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
CountySANTA CLARA
Lot (acres)The size of the land the home sits on, from county records.0.17
ConstructionThe main material the home's frame and walls are built from.Wood (Unspecified)
RoofThe main material covering the roof, such as asphalt shingle or tile.Wood Shingle
HeatingThe type of heating system in the home.Yes
FireplaceWhether the home has a fireplace, and what kind.Yes
PoolWhether the property has a pool, and what kind, such as in-ground.No

Transaction History(9)

Sales and refinances filed with the county for this home. Not every transfer is a normal sale, so check the type before comparing prices.

Assigned SchoolsThe public schools this address is zoned for. Boundaries change, so confirm with the district before you count on it.

M
Kennedy Middle SchoolA+
Middle · Grades 6–8 · 0.3 mi
H
Monta Vista High SchoolA+
High · Grades 9–12 · 0.5 mi
E
Abraham Lincoln Elementary SchoolA+
Elementary · Grades KG–5 · 0.5 mi

District: Cupertino Union Elementary School District

Neighborhood · ZIP 95014These are comparison scores, not percentages. 100 equals the national average, so 150 means about 50% above average.

CrimeLocal crime compared with the rest of the country, where 100 is average. It reflects things like population density, income, and how crime gets reported.78
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.84
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.512

Index scale: 100 = US average (tick). Lower is better.

Homes occupiedThe share of homes here that someone lives in. The rest sit empty, including vacation and for-sale homes.94%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.34%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.5.1%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.1.4%
PopulationHow many people live in this area.61,980
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.2,152 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$196,708
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$250,202
Average tempThe average temperature here across a full year.58°F
Annual precipHow much rain and melted snow falls here in a typical year.29 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.73%

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Data by ATTOM. Valuations are automated estimates, not appraisals. Photos from Google Street View and may not depict the current property state.

How this home compares

21663 Castleton St measured against every home in its neighborhood, its ZIP code and its county, using county assessor records refreshed nightly. A home can stand out in one of those areas and look ordinary in another, because each one holds a different mix of homes.

  • Worth more than 93% of homes in Cupertino 95014
  • Costs more per square foot than 85% of homes in Santa Clara County
  • Bigger than 88% of homes in Santa Clara County
  • Has a smaller lot than 74% of homes in Monta Vista North

What homes are worth in Cupertino 95014

Each bar is how many homes fall in that price range. The marker is this home.

This home
$838K$4.8M

This home is worth more than 93% of homes in Cupertino 95014.

How it measures up in Cupertino 95014

The dot is this home. The mark in the middle is the typical home in Cupertino 95014.

Estimated value$4,092,886
CheaperTypical $2,703,569Pricier

Pricier than 93% of homes nearby

Price per ft²$1450
CheaperTypical $1346Pricier

Pricier than 61% of homes nearby

Living area2,822 ft²
SmallerTypical 1,890 ft²Bigger

Bigger than 84% of homes nearby

Lot size0.17 ac
SmallerTypical 0.16 acBigger

Bigger than 56% of homes nearby

Year built1966
OlderTypical 1969Newer

Newer than 43% of homes nearby

How 21663 Castleton St ranks against every home in each area.
MeasureThis homeMonta Vista NorthCupertino 95014Santa Clara County
Estimated valuepricier than$4,092,88689% of homes93% of homes93% of homes
Price per ft²pricier than$145049% of homes61% of homes85% of homes
Living areabigger than2,822 ft²83% of homes84% of homes88% of homes
Lot sizebigger than0.17 ac26% of homes56% of homes69% of homes
Year builtnewer than196642% of homes43% of homes42% of homes

About 21663 Castleton St

How much is 21663 Castleton St, Cupertino, CA worth?

The TopHap Estimate for 21663 Castleton St, Cupertino, CA is $4,092,886 as of Aug 30, 2026. The likely range is $3,943,946 to $4,241,826. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 21663 Castleton St, Cupertino, CA last sell?

21663 Castleton St, Cupertino, CA last sold on Feb 14, 2007 for $1,575,000, according to the county's recorded deed.

How big is 21663 Castleton St, Cupertino, CA?

21663 Castleton St, Cupertino, CA has 5 bedrooms, 3 bathrooms, 2,822 square feet of living space and a 0.17-acre lot.

When was 21663 Castleton St, Cupertino, CA built?

21663 Castleton St, Cupertino, CA was built in 1966, making it 60 years old. The building has 2 stories.

What schools serve 21663 Castleton St, Cupertino, CA?

21663 Castleton St, Cupertino, CA is assigned to Kennedy Middle School (middle), rated A+; Monta Vista High School (high), rated A+; Abraham Lincoln Elementary School (elementary), rated A+. All sit in Cupertino Union Elementary School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 21663 Castleton St, Cupertino, CA compare to other homes in Cupertino 95014?

Among the 16,326 homes in Cupertino 95014, it is worth more than 93% of them ($4,092,886 against a typical $2,703,569), its price per square foot is higher than 61% of them ($1450 against a typical $1346), it is bigger than 84% of them (2,822 ft² against a typical 1,890 ft²), its lot is bigger than 56% of them (0.17 ac against a typical 0.16 ac) and it is newer than 43% of them (1966 against a typical 1969). Measured against all of Santa Clara County, it is worth more than 93% of homes there. These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 21663 Castleton St, Cupertino, CA?

The 2025 property tax bill for 21663 Castleton St, Cupertino, CA was $25,660. The county assessed it at $2,152,357.

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