As of the 2001 Census of India, Niwari had a population of 20,711 with the 606,00 km2 area. Males constitute 53% of the population and females 47%.
The 2001 Census of India provided data on Niwari's population (20,711) and its geographical area (606,00 square kilometers). The male population constituted 53% while the female population made up 47%.