As of the census of 2000, there were 12,983 people, 4,971 households, and 3,365 families residing in the city. The population density was 2,092.5 people per square mile (808.5/km²). There were 5,142 housing units at an average density of 320.2 persons/km² (828.8 persons/sq mi). The racial makeup of the city was 95.48% White, 0.27% African American, 0.75% Native American, 2.22% Asian, 0.07% Pacific Islander, 0.30% from other races, and 0.91% from two or more races. 0.79% of the population were Hispanic or Latino of any race.
There were 4,971 households out of which 35.5% had children under the age of 18 living with them, 55.0% were married couples living together, 8.7% have a woman whose husband does not live with her, and 32.3% were non-families. 26.6% of all households were made up of individuals and 12.3% had someone living alone who was 65 years of age or older. The average household size was 2.57 and the average family size was 3.16.
In the city the population was spread out with 27.7% under the age of 18, 8.6% from 18 to 24, 30.5% from 25 to 44, 19.4% from 45 to 64, and 13.7% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 97.0 males. For every 100 females age 18 and over, there were 94.4 males.
The median income for a household in the city was $43,980, and the median income for a family was $50,187. Males had a median income of $38,880 versus $22,830 for females. The per capita income for the city was $18,748. 4.8% of the population and 2.6% of families were below the poverty line. Out of the total people living in poverty, 4.6% are under the age of 18 and 10.4% are 65 or older.
Kaukauna is located at the intersections of several major roads. US 41, which forms the backbone of the Fox Cities region's transit network, runs along the northern edge of the city, where it intersects State Highway 55. 55, State Highway 96, and two busy county roads serve as important streets within the city. US 10 is just to the south of Kaukauna, and Fox Cities beltway Highway 441 is just to the west.
Kaukauna is also a member of Valley Transit, which provides bus service.