When is Dhanteras?धनतेरस कब है?

Hindu date: Kartika Krishna Trayodashi (Ashwin Krishna Trayodashi in the Amanta calendar).

It is kept on the day Trayodashi prevails in Pradosh Kaal, when the Lakshmi-Kubera puja and the Yama Deepam are done.

Dates are calculated for New Delhi; elsewhere they can fall a day earlier or later. Month names follow the Purnimanta calendar used in North India, where a month ends on Purnima. How we calculate

Dhanvantari is said to have risen from the churning of the ocean holding the pot of nectar on this day. Another story tells of King Hima's son, fated to die of snakebite on the fourth night of his marriage, whose wife kept him awake with lamps and stories while her jewels shone at the door, so that Yama turned back. Hence the Yama Deepam, a lamp placed facing south.