Carlstadt, NJ has a population of 6,238 and is the 5,607th largest city in the United States. The population density is 1,581 per sq mi which is 157966% higher than the New Jersey average and 1645% higher than the national average. The median age in Carlstadt is 40 which is approximately 2% higher than the New Jersey average of 40. In Carlstadt, 58% of the population over 15 years of age are married, 53% speak English and 24% speak Spanish. 58% of Carlstadt residents were born in New Jersey, 13% were born out of state, 0% were born outside of the United States and 29% were foreign born.