Municipality Žalec, which is part of the Savinjska statistical region, measures 117 km2; this ranks it 54th among Slovene municipalities.
Statistical data for 2019 reveal the following:
In the middle of 2019 about 21,430 people (about 10,790 men and 10,630 women) were living in the municipality, which ranks Žalec 16th among Slovene municipalities. The population density was 183 people per square kilometre, which was higher than the national average of 103 people per square kilometre.
The number of live births was higher than the number of deaths, which means that natural increase per 1,000 population in the municipality was positive. It was 0.1 (in Slovenia -0.6). 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 7.1. The sum of natural increase and net migration per 1,000 population in the municipality was positive. It was 7.2 (in Slovenia 7.2).
The mean age of people in Žalec was 44.0 years, which was higher than the national average (43.4).
As in most Slovene municipalities, in Žalec the number of old people was higher than the number of young people: there were 137 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 133. It also shows that the mean age of people in Žalec 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 two (Jezersko and Loški Potok) higher than the ageing index for men. In Žalec – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was the same.
Žalec had 12 kindergartens. They were attended by 900 children or 84% of all children aged 1–5, which was more than the national average of 81%. In the school year 2019/20 elementary schools in Žalec were attended by about 2,130 pupils, while various upper secondary schools were attended by about 750 pupils. There were 33 students and 6 graduates per 1,000 people in the municipality; in Slovenia the averages were 37 per 1,000 and 8 per 1,000, respectively.
Among people aged 15–64 (i.e. working age population) about 65% were persons in employment (i.e. persons in paid employment or self-employed persons), which is less than the national average (66%).
In Žalec, average monthly gross earnings per person employed by legal persons were about 13% lower than the annual average of monthly earnings for Slovenia; net earnings were about 12% lower.
Among 100 inhabitants in the municipality, 57 had a passenger car. The car was on average 11 years old.
In 2019, 364 kg of municipal waste per person was collected in Žalec, which is 5 kg more than on average in Slovenia.