Thandalai is a village in Udayarpalayam tehsil in district of Ariyalur, Tamil Nadu, India. As per the data provided by Census of India in 2011, total population of Thandalai was 5,390 which includes 2,704 males and 2,686 females. Thandalai covers 817.01 ha area. Pincode of Thandalai is 621803.