PIN code structure explained
A Postal Index Number is six digits long, and the digits are not random. Read left to right, they narrow the country down to a single delivery post office.
The six digits, position by position
- Digit 1 — the postal region. Nine values cover the country, one of them reserved for the Army Postal Service.
- Digit 2 — the sub-region within that postal region, usually a state or a group of smaller states and union territories.
- Digit 3 — the sorting district. Together with the first two digits it identifies the sorting office that routes the mail.
- Digits 4 to 6 — the specific delivery post office inside that sorting district.
So in 500072, "5" is the southern region, "50" narrows it to Telangana and Andhra Pradesh, "500" is the Hyderabad sorting district, and "072" is one delivery office within it.
First digit by postal region
| First digit | Region | States and union territories |
|---|---|---|
| 1 | Northern | Delhi, Haryana, Punjab, Himachal Pradesh, Jammu & Kashmir, Ladakh, Chandigarh |
| 2 | Northern | Uttar Pradesh, Uttarakhand |
| 3 | Western | Rajasthan, Gujarat, Daman & Diu, Dadra & Nagar Haveli |
| 4 | Western | Maharashtra, Madhya Pradesh, Chhattisgarh, Goa |
| 5 | Southern | Telangana, Andhra Pradesh, Karnataka |
| 6 | Southern | Kerala, Tamil Nadu, Puducherry, Lakshadweep |
| 7 | Eastern | West Bengal, Odisha, Assam and the North-Eastern states, Andaman & Nicobar Islands |
| 8 | Eastern | Bihar, Jharkhand |
| 9 | Army Postal Service | Field post offices of the armed forces |
Why one PIN code can cover several areas
The last three digits point at a delivery post office, and one office usually serves several localities. That is why a PIN code page can list multiple areas and more than one post office — typically one delivery office plus branch offices attached to it.
Using the structure to sanity-check an address
If the first two digits do not match the state on the envelope, the code is almost certainly wrong. Check the state's range in the state directory and then confirm the exact office. The lookup guide walks through it step by step.