How are seats numbered inside a coach?

Seats and berths in Indian Railway coaches follow a standard numbering system. Lower berths are numbered 1 to 72 in Sleeper and AC 3 Tier coaches, with side lower berths numbered separately. The berth number tells you the coach position as well. For example berth 23 in coach B1 means your seat is in the second coach of that class. In chair car coaches, seats are numbered in rows with an alphabet suffix like 12A, 12B, or 12C where A is window, B is middle, and C is aisle. This numbering helps you locate your seat even before boarding the train.