Most Frequently Asked Questions

I am a new ACS data user. Where can I access data for my community?  

Data.census.gov is the Census Bureau’s primary tool for accessing social, economic, housing, and demographic data from the ACS. For tutorials and other how-to materials on data.census.gov, visit the Census Bureau’s website. The Census Bureau’s ACS website is a comprehensive source of information about the ACS and the different ways to access the data.  

The ACS Online Community also includes a Resources page with links to several key Census Bureau and external resources on the ACS.

How can I find ACS data for a particular ZIP Code?

The Census Bureau does not produce population data at the ZIP Code level, but rather ZIP Code Tabulation Areas (ZCTAs), which are generalized representations of U.S. Postal Service ZIP Code service areas. The Census Bureau produced a short video that explains how ZCTAs differ from ZIP Codes.

Where can I find information about changes to the ACS Summary File format?

Information about the new ACS Summary File format is available on the Census Bureau’s website.

How did the COVID-19 pandemic affect the ACS?

The coronavirus pandemic severely America’s data infrastructure—including the ACS. Due to the impact of the COVID-19 pandemic on ACS data collection in 2020, the Census Bureau released a series of experimental estimates from the ACS 1-year data. However, after revising its methodology to reduce nonresponse bias in data collected in 2020, the Census Bureau determined the ACS 5-year estimates were fit for public release.

How can I access ACS data on business establishments?

The ACS is a household survey and does not include information about business establishments, but Census Business Builder provides selected demographic and economic data from the ACS and other sources for small business owners, chambers of commerce, and regional planning staff.

I am trying to access ACS data through the Census Bureau’s API. Where can I find guidance and sample code?

The Census Bureau has several resources to help you get started, including:

How do I calculate margins of error for derived ACS estimates?

The Census Bureau publishes a wide range of ACS estimates through the data products provided in data.census.gov. However, for some applications, you may need to construct custom ACS estimates and their associated margins of error. Formulas for calculating these margins of error are available in Chapter 8 of the ACS Handbook on Understanding and Using American Community Survey Data: What All Data Users Need to Know. You can also view the Census Bureau’s recent webinar on Calculating Margins of Error the ACS Way for more information.

Why are some of the data in my data.census.gov table missing?

Missing data in data.census.gov can be caused by data suppression. The Census Bureau applies various methods or restrictions to ACS data to limit the disclosure of information about individual respondents and to reduce the number of statistically unreliable estimates. More information is available on the Census Bureau’s ACS website.

I can’t find the data I need in data.census.gov. What should I do?

As a first step, check the Census Bureau’s Table Shells and Table List page to see if the ACS data you need are available in a published table. If not, you may be able to access them through the Public Use Microdata Sample (PUMS) Files, which allow data users to create custom estimates and tables, free of charge, that are not available through ACS pretabulated data products. Visit the Census Bureau’s ACS website for information about the ACS PUMS files and how to access them. 

When does the Census Bureau update the boundary files they use for different geographic areas?

The Census Bureau’s Geography Boundaries by Year page includes information about the geographic areas receiving published ACS estimates and the year or “vintage” of geographic boundaries.

Where can I find ACS data for detailed racial/ethnic groups?

Many published ACS estimates are available for different racial and ethnic groups. However, in data.census.gov, these data are often available in separate tables. For example, 2020 ACS estimates on AGE by DISABILITY STATUS are available through the following tables:

  • B18101A: AGE BY DISABILITY STATUS (WHITE ALONE)
  • B18101B: AGE BY DISABILITY STATUS (BLACK OR AFRICAN AMERICAN ALONE)
  • B18101C: AGE BY DISABILITY STATUS (AMERICAN INDIAN AND ALASKA NATIVE ALONE)
  • B18101D: AGE BY DISABILITY STATUS (ASIAN ALONE)
  • B18101E: AGE BY DISABILITY STATUS (NATIVE HAWAIIAN AND OTHER PACIFIC ISLANDER ALONE)
  • B18101F: AGE BY DISABILITY STATUS (SOME OTHER RACE ALONE)
  • B18101G: AGE BY DISABILITY STATUS (TWO OR MORE RACES)
  • B18101H: AGE BY DISABILITY STATUS (WHITE ALONE, NOT HISPANIC OR LATINO)
  • B18101I: AGE BY DISABILITY STATUS (HISPANIC OR LATINO)

These naming conventions (e.g., A= White Alone, I = Hispanic or Latino) are the same across all the Census Bureau’s ACS tables iterated by race/ethnicity.

Data for many population subgroups are also available through the Census Bureau’s Selected Population Profiles, which provide broad social, economic, and housing profiles for a large number of race, ethnic, ancestry, and country/region of birth groups.

The Census Bureau’s Table Shells and Table List webpage provides information about the ACS tables available for different years.

ACS data for more detailed racial and ethnic groups are published every five years through the Census Bureau’s Selected Population Tables and American Indian and Alaska Native Tables.

Or you can create your own racial/ethnic categories using the Census Bureau’s ACS Public Use Microdata Sample files.