Municipality Zagorje ob Savi, which is part of the Zasavska statistical region, measures 147 km2; this ranks it 43rd among Slovene municipalities.
Statistical data for 2023 reveal the following:
In the middle of 2023 about 16,520 people (about 8,280 men and 8,240 women) were living in the municipality, which ranks Zagorje ob Savi 30th among Slovene municipalities. The population density was 112 people per square kilometre, which was higher than the national average of 105 people per square kilometre.
The number of live births was lower than the number of deaths, which means that natural increase per 1,000 population in the municipality was negative. It was –0.9 (in Slovenia –2.1). The number of people who moved from the municipality was lower than the number of people who moved into the municipality, so net migration per 1,000 population in the municipality was positive. It was 4.2. The sum of natural increase and net migration per 1,000 population in the municipality was positive. It was 3.3 (in Slovenia 3.3).
The mean age of people in Zagorje ob Savi was 44.5 years, which was higher than the national average (44.1).
As in most Slovene municipalities, in Zagorje ob Savi the number of old people was higher than the number of young people: there were 150 people, aged 65 or more, per 100 people aged 0–14. This ratio shows that the value of the ageing index was higher than the national average of 145. It also shows that the mean age of people in Zagorje ob Savi is growing more rapidly than in Slovenia as a whole. Data by sex show that the ageing index for women was in all municipalities except in six (Črna na Koroškem, Dobrovnik/Dobronak, Grad, Hodoš/Hodos, Jezersko in Mislinja) higher than the ageing index for men. In Zagorje ob Savi – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was the same.
Zagorje ob Savi had 5 kindergartens, which were attended by 637 children. Of all children in the municipality aged 1–5, 85% were included in kindergartens, which was more than the national average of 83%. In the school year 2023/24 elementary schools in Zagorje ob Savi were attended by about 1,550 pupils, while various upper secondary schools were attended by about 640 pupils. There were 36 students and 7 graduates per 1,000 people in the municipality; in Slovenia the averages were 38 per 1,000 and 8 per 1,000, respectively.
Among people aged 15–64 (i.e. working age population) about 71% were persons in employment (i.e. persons in paid employment or self–employed persons), which is more than the national average (69%).
In Zagorje ob Savi, average monthly gross earnings per person employed by legal persons were about 12% lower than the annual average of monthly earnings for Slovenia; net earnings were about 10% lower.
Among 1,000 inhabitants in the municipality, 565 had a passenger car. The car was on average 11 years old.
In 2023, 314 kg of municipal waste per person was collected in Zagorje ob Savi, which is 64 kg less than on average in Slovenia.