The size of Sydenham is approximately 3.6 square kilometres. It has 25 parks covering nearly 6.5% of total area. The population of Sydenham in 2011 was 10,323 people. By 2016 the population was 10,829 showing a population growth of 4.9% in the area during that time. The predominant age group in Sydenham is 20-29 years. Households in Sydenham are primarily couples with children and are likely to be repaying $1400 - $1799 per month on mortgage repayments. In general, people in Sydenham work in a clerical occupation. In 2011, 68.4% of the homes in Sydenham were owner-occupied compared with 64.8% in 2016. Currently the median sales price of houses in the area is $706,000.