What is now the KMA was first legally defined as the Calcutta Metropolitan Planning Area in the schedule of the Calcutta Metropolitan Planning Area (Use and Development of Land) Control Act, 1965 (West Bengal Act XIV of 1965).[6] After repeal of that Act, the area was redefined as the Calcutta Metropolitan Area (CMA) in the first schedule of West Bengal Town and Country (Planning and Development) Act, 1979 (West Bengal Act XIII of 1979).[7]
According to the 2011 census data, the total population of the Kolkata metropolitan area was 14,112,536. KMDA report states the total area is 1,888 km2, making the population density 7,480 per km2.