How many adults aged 18 to 24 are there in the US, and who are they?

There were 31,936,859 people aged 18 to 24 in the US on 1 July 2025, according to the Census Bureau's Vintage 2025 population estimates, released in June 2026. That is out of a total US population of 341,784,857. Of the 18 to 24 year olds, 16,333,881 were men and 15,602,978 were women. The same series puts the age group at 32,095,193 a year earlier, so the count was slightly lower in 2025.

That answers the census question behind population aged 18 to 24. It does not tell you where a 20 year old is at nine on a Tuesday morning: on a campus, at work or at home. That is usually what a planner or a campaign team needs to know. This post sets out the published figures on who 18 to 24 year olds are, then shows how Cambium AI's EIKOS answers the question of where.

Where do 18 to 24 year olds live?

Most live in a parent's home. In 2025, 58.8% of men and 56.4% of women aged 18 to 24 lived in their parents' home, according to the Census Bureau's historical tables on the living arrangements of adults (table AD-1, from the 2025 Current Population Survey). One detail changes how to read this: the survey counts unmarried college students living in dormitories as living in their parents' home. So the share includes many students who spend much of the year on a campus.

How many are in college?

Close to half of those aged 18 to 21 are. In October 2024, 47.5% of 18 and 19 year olds and 49.4% of 20 and 21 year olds were enrolled in college, undergraduate or graduate, according to the Census Bureau's 2024 school enrollment tables. Among 22 to 24 year olds, the share was 25.5%. A further 18.3% of 18 and 19 year olds were still in high school.

How many young adults have a job?

Most of those in their early twenties do. In 2025, 65.4% of people aged 20 to 24 were employed, and 71.4% were in the labor force, meaning they had a job or were looking for one, according to the BLS table of employment status by age. Among 18 and 19 year olds, 42.6% were employed and 49.1% were in the labor force. The unemployment rate was 13.3% for 18 and 19 year olds and 8.3% for 20 to 24 year olds, against 4.3% for everyone aged 16 and over.

So the band changes fast. An 18 year old is often still in school or starting college. A 23 year old is more likely to be in work. One plan for all of "18 to 24" will fit some of it better than the rest.

Where are young adults during the day?

National tables cannot answer this, and it is the question EIKOS was built for. EIKOS, from Cambium AI, shows how an area's residents are likely to spend an ordinary day. Each dot on its map is a simulated resident with a home and a daily schedule, and a job and a commute where they have one. Press play and the day runs hour by hour, on a weekday, a Saturday or a Sunday. Click a resident to see their age, education, job, income and household size, and what they are doing at that moment.

Every resident is synthetic, modelled statistically from census and national survey data, and the simulation contains no personal data. Why Cambium AI built it, and a worked example for Boston, are set out in why we built EIKOS.

What could you use EIKOS for?

1. Planning around a college. The survey counts dorm students at their parents' address, so national figures cannot show where students are in term time. EIKOS lets a planner watch an ordinary weekday in their own area, hour by hour, and click through the residents who are there.
2. Transport and access to services. With 65.4% of 20 to 24 year olds in work, the commute matters. EIKOS gives each working resident a commute, and its analysis covers proximity to services, transit and schools.
3. Housing and new development. EIKOS sets population, household composition and housing next to the development pipeline, and compares current conditions with future scenarios. In the Boston example, a view set to 2032 shows planned buildings in Allston among today's city.
4. Making the case for funding. The EIKOS planning report names its sources and states its gaps and limitations, so a finding can go into a plan, a study or a grant application with its evidence attached.
5. Timing and place for a campaign. Marketing teams can use the same view to see where and when an area's residents are likely to be, on a weekday or at the weekend, before choosing locations and timing.

For other audience profiles built from published government figures, see people who work from home and marketing managers.

Where the numbers have limits

EIKOS is built on Cambium AI's synthetic populations. It shows where residents are likely to be, not where any real person is, and the judgment stays with the user. To see how EIKOS would work for your area, book a demo. If young adults are the audience for your next campaign, the Cambium AI marketing pilot tests the audience and the creative before money is spent.

Data sources: U.S. Census Bureau, Vintage 2025 Population Estimates, Annual Estimates of the Resident Population for Selected Age Groups by Sex (NC-EST2025-AGESEX, released June 2026); Current Population Survey, Annual Social and Economic Supplement 2025, table AD-1; Current Population Survey, October 2024 School Enrollment Supplement, table 1. U.S. Bureau of Labor Statistics, Current Population Survey, 2025 annual averages, table 3.