Municipality Šmarje pri Jelšah, which is part of the Savinjska statistical region, measures 108 km2; this ranks it 62nd among Slovene municipalities.
Statistical data for 2021 reveal the following:
In the middle of 2021 about 10,380 people (about 5,190 men and 5,190 women) were living in the municipality, which ranks Šmarje pri Jelšah 54th among Slovene municipalities. The population density was 96 people per square kilometre, which was lower than the national average of 104 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 -3.2 (in Slovenia -2.0). 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 1.8. The sum of natural increase and net migration per 1,000 population in the municipality was negative. It was -1.3 (in Slovenia -0.9).
The mean age of people in Šmarje pri Jelšah was 43.3 years, which was lower than the national average (43.8).
As in most Slovene municipalities, in Šmarje pri Jelšah the number of old people was higher than the number of young people: there were 122 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 139. It also shows that the mean age of people in Šmarje pri Jelšah 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 five (Črna na Koroškem, Dobrovnik/Dobronak, Jezersko, Loški Potok in Mislinja) higher than the ageing index for men. In Šmarje pri Jelšah – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was the same.
Šmarje pri Jelšah had 8 kindergartens, which were attended by 410 children. Of all children in the municipality aged 1–5, 84% were included in kindergartens, which was more than the national average of 81%. In the school year 2021/22 elementary schools in Šmarje pri Jelšah were attended by about 990 pupils, while various upper secondary schools were attended by about 430 pupils. There were 41 students and 8 graduates per 1,000 people in the municipality; in Slovenia the averages were 39 per 1,000 and 8 per 1,000, respectively.
Among people aged 15–64 (i.e. working age population) about 68% were persons in employment (i.e. persons in paid employment or self-employed persons), which is more than the national average (67%).
In Šmarje pri Jelšah, average monthly gross earnings per person employed by legal persons were about 6% lower than the annual average of monthly earnings for Slovenia; net earnings were about 5% lower.
Among 1,000 inhabitants in the municipality, 600 had a passenger car. The car was on average 11 years old.
In 2021, 276 kg of municipal waste per person was collected in Šmarje pri Jelšah, which is 89 kg less than on average in Slovenia.