22.11% of Karo Regency's population in 2024 will be aged 0-14 years.

The majority of the population in this region, or about 65.85%, are of working age, namely those aged 15-59 years, totaling 275,700. According to a 2024 publication by the Central Bureau of Statistics (BPS), the number reached 275,700. The remaining population consists of those aged 0-14 years (children), approximately 22.11%, and 12.05% are in the elderly group aged over 60 years.

The population of Karo Regency was recorded at 418,700 as of 2024. This figure increased compared to 2023 and is higher than in December 2021. Compared to five years earlier, the region's Compound Annual Growth Rate (CAGR) is recorded as lower. The growth over the last five years was recorded at 0.44%.

Compared to other areas in North Sumatra Province, this regency/city ranks tenth in nominal terms; while by island, it ranks 52nd.

The following is the population by age in Karo Regency in June 2024, sourced from a publication by the Central Bureau of Statistics (BPS):

* Age 0-4 years: 18,840 (4.5%)
* Age 5-9 years: 33,870 (8.09%)
* Age 10-14 years: 39,860 (9.52%)
* Age 15-19 years: 36,980 (8.83%)
* Age 20-24 years: 38,180 (9.12%)

* Age 25-29 years: 34,080 (8.14%)
* Age 30-34 years: 30,320 (7.24%)
* Age 35-39 years: 29,490 (7.04%)
* Age 40-44 years: 31,130 (7.43%)
* Age 45-49 years: 28,370 (6.77%)
* Age 50-54 years: 25,830 (6.17%)
* Age 55-59 years: 21,330 (5.09%)
* Age 60-64 years: 16,440 (3.93%)
* Age 65-69 years: 12,270 (2.93%)
* Age 70-74 years: 9,130 (2.18%)
* Age 75 years and over: 12,600 (3.01%)