According to the 2021 Census of Population by Statistics Canada, the Town of Magrath had a population of 2,481, residing in 803 out of 830 total private dwellings. This represents a 4.5% increase from the 2016 population of 2,374. With a land area of 5.88 km² (2.27 sq mi), the population density in 2021 was 421.9 people per km² (1,092.8 per sq mi).

The Town of Magrath's 2017 municipal census recorded a population of 2,435, marking a 1.5% increase from the 2015 municipal census, which reported 2,398 residents.

In the 2016 Census, Statistics Canada reported the Town of Magrath had a population of 2,374, living in 757 of its 794 private dwellings. This was a 7.1% increase from the 2011 population of 2,217. The town had a land area of 5.99 km² (2.31 sq mi) and a population density of 396.3 people per km² (1,026.5 per sq mi) in 2016.