Municipality Vojnik, which is part of the Savinjska statistical region, measures 75 km2; this ranks it 93rd among Slovene municipalities.
Statistical data for 2019 reveal the following:
In the middle of 2019 about 8,850 people (about 4,430 men and 4,420 women) were living in the municipality, which ranks Vojnik 58th among Slovene municipalities. The population density was 118 people per square kilometre, which was higher than the national average of 103 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 -2.6 (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 14.1. The sum of natural increase and net migration per 1,000 population in the municipality was positive. It was 11.5 (in Slovenia 7.2).
The mean age of people in Vojnik was 43.4 years, which was the same as the national average.
As in most Slovene municipalities, in Vojnik the number of old people was higher than the number of young people: there were 128 people, aged 65 or more, per 100 people aged 0–14. This ratio shows that the value of the ageing index was lower than the national average of 133. It also shows that the mean age of people in Vojnik is growing more slowly 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 Vojnik – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was the same.
Vojnik had 6 kindergartens. They were attended by 426 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 Vojnik were attended by about 890 pupils, while various upper secondary schools were attended by about 340 pupils. There were 40 students and 8 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 69% were persons in employment (i.e. persons in paid employment or self-employed persons), which is more than the national average (66%).
In Vojnik, average monthly gross earnings per person employed by legal persons were about 16% lower than the annual average of monthly earnings for Slovenia; net earnings were about 13% lower.
Among 100 inhabitants in the municipality, 59 had a passenger car. The car was on average 10 years old.
In 2019, 365 kg of municipal waste per person was collected in Vojnik, which is 6 kg more than on average in Slovenia.