PIN stands for Postal Index Number — a 6-digit code introduced by India Post in 1972. The first digit indicates the postal zone (1 = Delhi/Haryana, 2 = UP, etc.) and the last 3 digits identify the delivery Post Office.

Head Post Office (HPO): Top-level office in a district. Sub Post Office (SPO): Reports to the HPO. Branch Post Office (BPO): Smallest unit, usually in villages or sub-localities.

One PIN code can serve multiple Post Offices in the same locality. All branches under the same PIN share the same delivery area — so any of them can receive your mail.

1 – Delhi, HP, J&K  |  2 – UP, Uttarakhand  |  3 – Rajasthan, Gujarat  |  4 – Maharashtra, MP, Goa  |  5 – AP, Karnataka  |  6 – Tamil Nadu, Kerala  |  7 – WB, NE States  |  8 – Bihar, Odisha