The size of St Clair is approximately 7.2 square kilometres. It has 19 parks covering nearly 9.5% of total area. The population of St Clair in 2011 was 19,837 people. By 2016 the population was 19,892 showing a population growth of 0.3% in the area during that time. The predominant age group in St Clair is 20-29 years. Households in St Clair are primarily couples with children and are likely to be repaying $1800 - $2399 per month on mortgage repayments. In general, people in St Clair work in a clerical occupation. In 2011, 81.5% of the homes in St Clair were owner-occupied compared with 79.3% in 2016. Currently the median sales price of houses in the area is $860,000.