As of the census of 2000, there are 50,546 people, 18,204 households, and 13,616 families residing in the city. The population density is 1,783.9/km² (4,620.5/mi²). There are 18,682 housing units at an average density of 659.3/km² (1,707.7/mi²). The racial makeup of the city is 50.14% White, 0.69% African American, 0.20% Native American, 44.44% Asian American, 0.13% Pacific Islander, 1.26% from other races, and 3.14% from two or more races. 3.98% of the population are Hispanic or Latino of any race.
There are 18,204 households out of which 41.6% have children under the age of 18 living with them, 63.9% are married couples living together, 7.8% have a female householder with no husband present, and 25.2% are non-families. 19.6% of all households are made up of individuals and 6.4% have someone living alone who is 65 years of age or older. The average household size is 2.75 and the average family size is 3.19.
In the city the population is spread out with 26.6% under the age of 18, 5.2% from 18 to 24, 33.0% from 25 to 44, 24.1% from 45 to 64, and 11.0% who are 65 years of age or older. The median age is 38 years. For every 100 females there are 99.5 males. For every 100 females age 18 and over, there are 96.8 males.
The median income for a household in the city is $100,411, and the median income for a family is $109,455. Males have a median income of $91,191 versus $58,375 for females. The per capita income for the city is $44,749. 4.8% of the population and 3.7% of families are below the poverty line. Out of the total people living in poverty, 4.6% are under the age of 18 and 5.0% are 65 or older.
It is sometimes referred to as the 'heart' of silicon valley, as worldwide headquarters for Apple Computer is located here. Several high-tech companies claim offices here, including Hewlett Packard, Symantec, and Sun Microsystems. Cupertino is also home to De Anza College.