How Are Population Projections Estimated?

Since collecting and processing demographic data takes several months, the most recent Census data is typically one to two years old. However, we understand many of you are looking for 2025 data, so we've provided estimates based on either the Census Population Estimates Program (PEP), when available, or their American Community Survey (ACS) dataset. Here's how.

1. When PEP data are available

If the Census Bureau publishes PEP data for a city or county, we calculate the percent change between the most recent year (2023) and the previous year (2022). Then we apply that same percent change to estimate the population in the next year (2024) and then the current year (2025).

2. When PEP aren't available

Not all cities have PEP estimates, and zip codes are not included in the PEP dataset. For these geographies, we use the 5-year ACS data. The most recent ACS data is for 2023. To estimate population changes, we calculate the percentage change for the population between 2023 and 2018 (the most recent non-overlapping year). Since 2025 is two years beyond 2023, we apply 40% of the total growth or decline over the 5-year period to project the population for 2025.

This simple methodology is effective because demographic changes typically occur gradually, allowing for reliable year-over-year projections using the best available data.

Read our FAQ here about why we can't compare the year-over-year data for the 5-year ACS: https://secure.helpscout.net/docs/5deab6cb04286364bc929799/article/5fbbd426cff47e0017d34804/