Understanding ZIP Code-Level Data Calculations

Learn more about ZIP code-level data and how SparkMap calculates it! ZIP code-level Community Needs Assessments are available to Premium Annual Subscribers only.

What’s a ZIP code?

What’s a ZCTA?

How SparkMap Calculates data for ZCTAs

1 – What’s a ZIP code?

ZIP codes are non-spatial designations by the United States Postal Service, created as a way to group mailing addresses. ZIP codes are not defined geographic boundaries and are updated frequently, based on factors such as population shifts and mail volume changes.

2 – What’s a ZCTA?

ZCTAs (ZIP Code Tabulation Areas) are geographic areas corresponding to ZIP codes. 

Because of the popularity of understanding neighborhoods and regions using the familiar language of ZIP codes, the Census Bureau created ZIP Code Tabulation Areas (ZCTAs) in the year 2000 as a geographic area corresponding to a ZIP Code. ZCTAs only change every 10 years and are a standard in neighborhood-level geography. 

SparkMap uses ZCTA boundaries, where appropriate, to align with the Census Bureau’s geographic standard. 

For more information about the differences between ZIP codes and ZCTAs, check out guidance on ZIP Code Tabulation Areas (ZCTAs) from the Census Bureau and All about ZIP Codes from the Missouri Census Data Center. 

3 – How SparkMap Calculates ZIP Code-Level Data for ZCTAs

Some data we utilize are already available at the ZCTA level, like measures from the American Community Survey.

Other data are initially only available at the county and Census tract-level. In these cases, we produce population-weighted ZCTA-level estimates based on the intersection of Census tracts and ZCTAs. We also provide ZCTA estimates for some sources originally available only at the county level. These are likewise population-weighted calculations.

Want to learn more? View our Small Area Estimation Graphic.