Sunnyvale, CA has a population of 149,596 and is the 175th largest city in the United States. The population density is 6,802 per sq mi which is 2827% higher than the California average and 7408% higher than the national average. The median age in Sunnyvale is 35 which is approximately 2% lower than the California average of 36. In Sunnyvale, 63% of the population over 15 years of age are married, 44% speak English and 13% speak Spanish. 36% of Sunnyvale residents were born in California, 16% were born out of state, 1% were born outside of the United States and 46% were foreign born.