India’s Postal Index Number — the PIN code — was introduced on 15 August 1972, the 25th anniversary of independence. Before that, mail was sorted by reading the address itself: the town, the district, the state. In a country with thousands of similar or identical place names, written in many scripts, that was slow and error-prone.
The problem it solved
A sorter in a big mail office had to know which of several villages called Rampur, or which of two districts called Aurangabad, an envelope was meant for. Addresses might be written in Hindi, Tamil, Bengali, English or a mix. Mistakes sent letters hundreds of kilometres in the wrong direction, and training new sorters took a long time because so much depended on memory.
A number solves both problems. Digits are the same in every language, and a sorter only needs to read a few of them to know where an item goes next.
Who designed it
The system is credited to Shriram Bhikaji Velankar, a senior official in the Ministry of Communications and a member of the Posts and Telegraphs Board at the time. He was also known as a Sanskrit scholar and poet. The design borrowed the idea of postal codes from other countries but fitted the digits to India’s own postal geography.
How the digits were laid out
The country was divided into eight geographical postal zones, numbered 1 to 8, with 9 reserved for the Army Postal Service. The first digit is the zone, the second narrows it to a sub-zone or postal circle, and the third identifies a sorting district. The last three digits identify the delivery post office within that sorting district. Our article on what each digit means walks through a worked example.
- 1 — Delhi, Haryana, Punjab, Himachal Pradesh, Jammu & Kashmir
- 2 — Uttar Pradesh, Uttarakhand
- 3 — Rajasthan, Gujarat
- 4 — Maharashtra, Madhya Pradesh, Chhattisgarh, Goa
- 5 — Andhra Pradesh, Telangana, Karnataka
- 6 — Tamil Nadu, Kerala, Puducherry, Lakshadweep
- 7 — West Bengal, Odisha, the North-East, Andaman & Nicobar
- 8 — Bihar, Jharkhand
- 9 — Army Postal Service
Why the zones still match old state lines
PIN codes follow postal geography, not political boundaries, and they rarely change when states are reorganised. When Uttarakhand, Jharkhand, Chhattisgarh and Telangana became separate states, their offices kept their existing codes. That is why Uttarakhand codes start with 2, like Uttar Pradesh, and Telangana codes start with 5, like Andhra Pradesh.
How big the network is today
India Post’s All India Pincode Directory (data.gov.in, 2021 snapshot) lists 19,299 PIN codes and 157,056 post offices — most of them small branch offices serving villages. You can browse all of them on this site, from state to district to individual office.
What came after the PIN code
The six-digit code is still the backbone of Indian addressing, used by India Post and every private courier. In 2025 the Department of Posts added a finer-grained digital address code, DIGIPIN, for exact locations; it complements the PIN code rather than replacing it. Our guide on DIGIPIN vs PIN code explains the difference.
More than fifty years on, the design has held up well. The only real change most people notice is that big cities keep gaining new codes as they grow.
FAQ
Did addresses have codes before 1972?
Some large cities used numbered postal districts before the national system — Bombay and Calcutta, for example — but there was no single scheme covering the whole country until the PIN code.
Has the six-digit format ever changed?
No. New codes have been added as post offices opened, but the format — six digits, read from region down to office — is the same as in 1972.