California 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 39.46M California population, the 25-29yrs age group constituted the highest percentage of the total population (7.58%), followed by the 30-34yrs age group (7.48%), and the 35-39yrs age group (7.03%).

In the case of age cohorts, Adults (18-64yrs) constituted the highest percentage of the total population (62.84%), followed by Children (0-17yrs) (22.79%), and Seniors (65yrs and Over) (14.37%).

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 other states, and the United States.

Related Topics: California ACS-5Yrs Estimates, 2021 Topic List.

Data Source: US Census - ACS 5-Year Estimates.

California Percentages of Population By Age Group in 2021

25-29yrs

30-34yrs

35-39yrs

10-14yrs

20-24yrs

15-19yrs

40-44yrs

45-49yrs

50-54yrs

55-59yrs

California Percentages of Population By Age Cohort in 2021

Adults (18-64yrs)

Children (0-17yrs)

Seniors (65yrs and Over)

California Population By Age Group in 2021

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Age Group	Number of People	% of Total
25-29yrs	2992210	7.58
30-34yrs	2949412	7.48
35-39yrs	2772679	7.03
10-14yrs	2658361	6.74
20-24yrs	2626849	6.66
15-19yrs	2588625	6.56
40-44yrs	2568370	6.51
45-49yrs	2532144	6.42
50-54yrs	2511259	6.37
55-59yrs	2502174	6.34
5-9yrs	2434113	6.17
Under 5yrs	2350335	5.96
60-64yrs	2298943	5.83
65-69yrs	1890299	4.79
70-74yrs	1473148	3.73
75-79yrs	940788	2.38
85yrs and Over	724961	1.84
80-84yrs	640683	1.62

California Population By Age Cohort in 2021

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Age Cohort	Number of People	% of Total
Adults (18-64yrs)	24793042	62.84
Children (0-17yrs)	8992432	22.79
Seniors (65yrs and Over)	5669879	14.37