According to 2011 census, Vellakovil had a population of 40,359 with a sex-ratio of 1,002 females for every 1,000 males, much above the national average of 929. A total of 3,438 were under the age of six, constituting 1,787 males and 1,651 females. Scheduled Castes and Scheduled Tribes accounted for 16.28% and 0.05% of the population respectively. The average literacy of the town was 74.37%, compared to the national average of 72.99%. The town had a total of 12,157 households. There were a total of 22,053 workers, comprising 577 cultivators, 1,776 main agricultural labourers, 1,077 in house hold industries, 17,098 other workers, 1,525 marginal workers, 30 marginal cultivators, 164 marginal agricultural labourers, 83 marginal workers in household industries and 1,248 other marginal workers.
