Simi Valley, CA population age distribution
A complete breakdown of Simi Valley's age demographics from 0 to 85 years, distributed across 18 age groups is listed in the table below.
Age Group | Population | % of Total Population |
---|---|---|
Under 5 years | 6,548 | 5.16% |
5 to 9 years | 6,068 | 4.79% |
10 to 14 years | 8,405 | 6.63% |
15 to 19 years | 8,312 | 6.55% |
20 to 24 years | 7,737 | 6.1% |
25 to 29 years | 8,606 | 6.79% |
30 to 34 years | 8,272 | 6.52% |
35 to 39 years | 7,757 | 6.12% |
40 to 44 years | 8,091 | 6.38% |
45 to 49 years | 9,532 | 7.52% |
50 to 54 years | 9,180 | 7.24% |
55 to 59 years | 9,797 | 7.73% |
60 to 64 years | 8,535 | 6.73% |
65 to 69 years | 6,849 | 5.4% |
70 to 74 years | 4,859 | 3.83% |
75 to 79 years | 3,510 | 2.77% |
80 to 84 years | 2,229 | 1.76% |
85 years and over | 2,522 | 1.99% |
TABLE OF CONTENTS
Simi Valley, CA population by age group
Sources: U.S. Census Bureau, American Community Survey (ACS) 2021

The largest age group in Simi Valley, CA was for the group of age 55-59 years with a population of 9,797 (7.73%), according to the 2021 American Community Survey.
At the same time, the smallest age group in Simi Valley, CA was the 80-84 years with a population of 2,229 (1.76%).
Simi Valley, CA population by age cohort
To better understand the age distribution of Simi Valley, CA's population, we divided it into the following 3 cohorts:
- Children : Under the age of 18 years
- Adults (working population): Between the age of 18 and 64 years
- Seniors: 65 years and above

Here's the population for each of the three cohorts.
Age Group | Population | % of Total Population |
---|---|---|
Under 18 years | 26,370 | 20.8% |
18 to 64 years | 80,470 | 63.46% |
85 years and over | 19,969 | 15.75% |
Key stats for each age cohort as per our analysis of U.S. Census Bureau American Community Survey:
- Simi Valley's population under 18 was 20.80%, compared to the 22.51% nationwide.
- Simi Valley's working population (between 18 and 64) was 63.46%, compared to 61.45% nationwide.
- Simi Valley's elderly or the senior population (over 65 age) was 15.75% as compared to 16.04% nationwide.
Simi Valley, CA population pyramid
Population pyramid for Simi Valley, CA is charted below using the estimates from U.S. Census Bureau's American Community Survey 5-Year estimates. A wide base suggests population increase, narrow base indicates declining birth rates.
Key stats from our analysis of the Simi Valley's population pyramid:
- Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for Simi Valley, CA, is 24.5.
- Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for Simi Valley, CA, is 23.3.
- Total dependency ratio for Simi Valley, CA is 47.8.
- Potential support ratio, which is the number of youth (working age population) per elderly, for Simi Valley, CA is 4.3.

Here's the Simi Valley, CA's male and female population across different age groups:
Age Group | Population(Male) | Population(Female) | Total Population |
---|---|---|---|
Under 5 years | 3,829 | 2,719 | 6,548 |
5 to 9 years | 2,960 | 3,108 | 6,068 |
10 to 14 years | 3,766 | 4,639 | 8,405 |
15 to 19 years | 4,223 | 4,089 | 8,312 |
20 to 24 years | 3,779 | 3,958 | 7,737 |
25 to 29 years | 4,265 | 4,341 | 8,606 |
30 to 34 years | 4,524 | 3,748 | 8,272 |
35 to 39 years | 4,000 | 3,757 | 7,757 |
40 to 44 years | 4,068 | 4,023 | 8,091 |
45 to 49 years | 4,722 | 4,810 | 9,532 |
50 to 54 years | 4,701 | 4,479 | 9,180 |
55 to 59 years | 4,848 | 4,949 | 9,797 |
60 to 64 years | 4,256 | 4,279 | 8,535 |
65 to 69 years | 2,905 | 3,944 | 6,849 |
70 to 74 years | 2,175 | 2,684 | 4,859 |
75 to 79 years | 1,507 | 2,003 | 3,510 |
80 to 84 years | 882 | 1,347 | 2,229 |
85 years and over | 789 | 1,733 | 2,522 |
Things to know
What is the population of Simi Valley, CA under 18?
Simi Valley's population under the age of 18 is 26,370, as per the latest U.S. Census Bureau's American Community Survey estimates. This population is 20.80% of the total resident population of Simi Valley, CA.
What is the aging population in Simi Valley, CA?
Simi Valley's population aged 65 years and above was 19,969. As per the U.S. Census Bureau's American Community Survey, this population is 15.75% of the entire population.
References
- U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates