Cochituate is located at 42°19'40" North, 71°21'37" West (42.327672, -71.360236)1.
According to the United States Census Bureau, it has a total area of 10.8 km² (4.2 mi²). 9.9 km² (3.8 mi²) of it is land and 0.8 km² (0.3 mi²) of it is water. The total area is 7.69% water.
As of the census of 2000, there are 6,768 people, 2,449 households, and 1,851 families residing in Cochituate. The population density is 682.3/km² (1,765.6/mi²). There are 2,516 housing units at an average density of 253.6/km² (656.4/mi²). The racial makeup of Cochituate is 90.90% White, 0.93% African American, 0.09% Native American, 6.24% Asian, 0.06% Pacific Islander, 0.24% from other races, and 1.55% from two or more races. 1.00% of the population are Hispanic or Latino of any race.
There are 2,449 households out of which 38.5% have children under the age of 18 living with them, 64.9% are married couples living together, 8.5% have a female householder with no husband present, and 24.4% are non-families. 19.7% of all households are made up of individuals and 9.0% have someone living alone who is 65 years of age or older. The average household size is 2.70 and the average family size is 3.14.
In Cochituate the population is spread out with 27.2% under the age of 18, 3.5% from 18 to 24, 25.5% from 25 to 44, 27.8% from 45 to 64, and 16.0% who are 65 years of age or older. The median age is 42 years. For every 100 females there are 91.3 males. For every 100 females age 18 and over, there are 85.8 males.
The median income for a household in Cochituate is $89,012, and the median income for a family is $101,362. Males have a median income of $71,500 versus $50,223 for females. The per capita income for Cochituate is $42,752. 2.2% of the population and 1.8% of families are below the poverty line. Out of the total people living in poverty, 1.1% are under the age of 18 and 4.3% are 65 or older.