The size of Calga is approximately 16.4 square kilometres. It has 3 parks covering nearly 46.7% of total area. The population of Calga in 2011 was 221 people. By 2016 the population was 129 showing a population decline of 41.6% in the area during that time. The predominant age group in Calga is 0-9 years. Households in Calga are primarily couples with children and are likely to be repaying $2400 - $2999 per month on mortgage repayments. In general, people in Calga work in a trades occupation. In 2011, 76.3% of the homes in Calga were owner-occupied compared with 73.4% in 2016.