Web page · IPUMS
DatasetIPUMS USA harmonised census microdata
Harmonised individual-level census and American Community Survey microdata going back to 1850, with an extract builder that lets you pick only the variables and years you need.
Published February 9, 2026
- Audience
- Analysts External partners
- Access
- Free account required
What do these mean?
- Analysts
- Research, data and evaluation staff.
- External partners
- Collaborating organizations outside your own.
- Free account required
- Free, but you have to register first.
What it is
IPUMS takes decades of census and survey microdata and does the tedious, essential work of harmonising it: the same variable means the same thing across years, with the exceptions documented rather than hidden. You build an extract on the site — choose samples, choose variables — and download only what you asked for.
Who it is for
Analysts who need to go below the published summary tables: custom age bands, cross-tabulations the pre-built tables do not offer, or a consistent series across more years than a single survey release covers.
What it takes to use it
Registration is free but required, and each extract takes a few minutes to build. Plan for the variable documentation to take longer than the download — comparability across years is usually the real work, and the notes on each variable are where the traps are described.
Notes from the library
Read the sample weights documentation before computing anything. Microdata without weights answers a different question than the one people usually mean, and this is the single most common mistake we see in draft analyses that use it.
About
- Year published
- 2026
- Contact email
- Fictional contact — demo only
Who it is for
- Topics
- demographics
- census
- microdata
- small-area analysis
- Language
- English