US Population By Age Group and Age Cohort in 2021 (ACS-5Yrs)
Updated on February 28, 2025.
Based on the US Census ACS-5Yrs estimates, in 2021, among the 329.73M US population, the 25-29yrs age group constituted the highest percentage of the total population (6.93%), followed by the 30-34yrs age group (6.83%), and the 55-59yrs age group (6.65%).
In the case of age cohorts, Adults (18-64yrs) constituted the highest percentage of the total population (61.45%), followed by Children (0-17yrs) (22.51%), and Seniors (65yrs and Over) (16.04%).
The first and second charts below shows the percentage of the population by age group and age cohort respectively. The table below also shows the number and percentages for each age group and age cohort.
You can see similar information for each state.
Related Topics: US ACS-5Yrs Estimates, 2021 Topic List.
Data Source: US Census - ACS 5-Year Estimates.
US Population By Age Group in 2021
Age Group | Number of People | % of Total |
|---|---|---|
| Under 5yrs | 19,423,121 | 5.89 |
| 85yrs and Over | 6,299,788 | 1.91 |
| 80-84yrs | 5,932,196 | 1.80 |
| 75-79yrs | 9,066,018 | 2.75 |
| 70-74yrs | 13,956,297 | 4.23 |
| 65-69yrs | 17,634,322 | 5.35 |
| 60-64yrs | 20,900,477 | 6.34 |
| 55-59yrs | 21,928,936 | 6.65 |
| 50-54yrs | 21,049,271 | 6.38 |
| 5-9yrs | 20,247,138 | 6.14 |
| 45-49yrs | 20,582,187 | 6.24 |
| 40-44yrs | 20,521,593 | 6.22 |
| 35-39yrs | 21,920,290 | 6.65 |
| 30-34yrs | 22,506,614 | 6.83 |
| 25-29yrs | 22,854,328 | 6.93 |
| 20-24yrs | 21,574,425 | 6.54 |
| 15-19yrs | 21,654,363 | 6.57 |
| 10-14yrs | 21,674,117 | 6.57 |
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US Population By Age Cohort in 2021
Age Cohort | Number of People | % of Total |
|---|---|---|
| Seniors (65yrs and Over) | 52,888,621 | 16.04 |
| Children (0-17yrs) | 74,234,075 | 22.51 |
| Adults (18-64yrs) | 202,602,785 | 61.45 |
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