The size of Colac is approximately 37.5 square kilometres. It has 11 parks covering nearly 1.2% of total area. The population of Colac in 2011 was 8,696 people. By 2016 the population was 9,066 showing a population growth of 4.3% in the area during that time. The predominant age group in Colac is 20-29 years. Households in Colac are primarily childless couples and are likely to be repaying $1000 - $1399 per month on mortgage repayments. In general, people in Colac work in a labourer occupation. In 2011, 67.4% of the homes in Colac were owner-occupied compared with 66.6% in 2016. Currently the median sales price of houses in the area is $425,000.