Municipality Šoštanj, which is part of the Savinjska statistical region, measures 96 km2; this ranks it 74th among Slovene municipalities.
Statistical data for 2013 reveal the following:
In the middle of 2013 about 8,800 people (about 4,550 men and 4,250 women) were living in the municipality, which ranks Šoštanj 58th among Slovene municipalities. The population density was 92 people per square kilometre, which was lower than the national average of 102 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 -1.2 (in Slovenia 0.9). 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 6.9. The sum of natural increase and net migration per 1,000 population in the municipality was positive. It was 5.7 (in Slovenia 1.1).
The mean age of people in Šoštanj was 41.6 years, which was lower than the national average (42.2).
As in most Slovene municipalities, in Šoštanj the number of old people was higher than the number of young people: there were 106 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 119. It also shows that the mean age of people in Šoštanj is growing more slowly than in Slovenia as a whole. Data by sex show that the ageing index for women was in all Slovene municipalities higher than the ageing index for men. In Šoštanj – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was exactly the opposite.
Šoštanj had 6 kindergarten. They were attended by 358 children or 75% of all children aged 1–5, which was the same as the national average.. In the school year 2013/2014 basic schools in Šoštanj were attended by about 770 pupils, while various upper secondary schools were attended by about 340 pupils. There were 50 students and 9 graduates per 1,000 people in the municipality; in Slovenia the averages were 44 per 1,000 and 9 per 1,000, respectively.
Among people aged 15–64 (i.e. working age population) about 60% were persons in employment (i.e. persons in paid employment or self-employed persons), which is more than the national average of 57%.
The registered unemployment rate was 11.9%, which is less than the national average (13.1%). As in most Slovene municipalities, more women than men were unemployed.
In Šoštanj, average monthly gross earnings per person employed by legal persons were about 11% higher than the annual average of monthly earnings for Slovenia; and net earnings about 10% higher.
In 2013, there were 352 dwellings per 1,000 population. About 66% of dwellings had at least three rooms. Average size of dwellings in the municipality was 89 m2.
Every other person in Šoštanj had a car (50 passenger cars per 100 population); cars in this municipality were on average 9 years old.
In 2013, 274 kg of municipal waste per person was collected in Šoštanj, which is 46 kg less than on average in Slovenia.