About this tool
The PIN Code Decoder explains the 6-digit Indian Postal Index Number (PIN) structure: position 1 = region, 2 = sub-region, 3 = sorting district, last 3 = specific post office.
How it works
Enter any 6-digit PIN code.
About the PIN code system
The Postal Index Number (PIN) is the six-digit code that India Post uses to route every letter, parcel, and registered article from the source sorting office to the delivery post office. It was introduced on 15 August 1972 by then Union Communications Minister Shriman Indra Kumar Gujral to deal with the post-Partition surge in look-alike place names, and it replaced the older manual sorting that relied on village names hand-written on covers.
India is divided into 9 PIN regions. Regions 1 through 8 are geographical: roughly North, Central North, West Central, West and Central, South-Central, South, East and North East, and East. Region 9 is reserved for the Army Postal Service (APO and FPO), where the actual deployment location is masked behind a base post office for operational security.
How the 6 digits decode
Each digit narrows the destination one step further. The PIN is a hierarchical address rather than a checksum, so every position carries independent geographic meaning.
PIN = R | S | D | OOO R = digit 1: PIN region (1 to 9) S = digit 2: sub-region within R (state cluster) D = digit 3: sorting district (head office routing) OOO = digits 4 to 6: specific delivery post office
- Digit 1 (Region): picks one of 9 macro zones.
- Digit 2 (Sub-region): usually maps to a state or large city cluster within that region.
- Digit 3 (Sorting district): the routing hub. Mail for the entire district arrives at one sorting office.
- Digits 4 to 6 (Post Office): the specific branch post office, sub post office, or head office that actually delivers to the address.
Worked example: decoding 560001 (Bangalore GPO)
- Digit 1 = 5: South region (Andhra Pradesh, Karnataka, Telangana).
- Digit 2 = 6: sub-region 56 maps to Karnataka.
- Digit 3 = 0: sorting district 560 is the Bangalore Urban routing zone.
- Digits 4 to 6 = 001: identifies Bangalore GPO, the head delivery office on Cubbon Road.
- Combined: 560001 routes a letter to the Bangalore General Post Office for final delivery anywhere it claims jurisdiction over.
Region reference table
| Digit 1 | Region | Major states and union territories | Example PIN |
|---|---|---|---|
| 1 | North | Delhi, Haryana, Punjab, Himachal Pradesh, J and K, Chandigarh | 110001 (New Delhi GPO) |
| 2 | North | Uttar Pradesh, Uttarakhand | 226001 (Lucknow GPO) |
| 3 | West | Rajasthan, Gujarat, Daman and Diu | 302001 (Jaipur GPO) |
| 4 | West Central | Maharashtra, MP, Chhattisgarh, Goa | 400001 (Mumbai GPO) |
| 5 | South | AP, Karnataka, Telangana | 500001 (Hyderabad GPO) |
| 6 | South | Tamil Nadu, Kerala, Puducherry | 600001 (Chennai GPO) |
| 7 | East | West Bengal, Odisha, Andaman, North East | 700001 (Kolkata GPO) |
| 8 | East | Bihar, Jharkhand | 800001 (Patna GPO) |
| 9 | APS | Army Postal Service field deployments | 901001 (APO Delhi base) |
Common pitfalls
- Confusing PIN with phone STD code. Both are short numbers tied to geography, but they share no digits. Mumbai phone STD is 022 while Mumbai PIN starts 4000xx.
- Assuming the 6 digits sum to a checksum. Unlike credit cards, PIN codes have no Luhn or modulo checksum. Any 6-digit string is structurally valid; the only verification is whether India Post has actually issued it.
- Mailing to a sorting district instead of a post office. Writing only the first 3 digits routes mail to the head sorting office, where it stalls without further routing. Always include all 6 digits.
- Stale PINs after India Post redistricting. India Post occasionally splits or merges delivery offices (notably across smart-city ward changes). Confirm new addresses via the India Post pincode finder before using older directory entries.
- Treating APO codes as civilian. A PIN starting with 9 cannot be reverse-geocoded to a civilian location. Most map APIs return null or wrong coordinates for APS codes.
- Mixing PIN with international formats. Many cross-border shipping tools auto-validate against US ZIP regexes (5 digits). They reject valid 6-digit Indian PINs unless the country code is set first.
Related calculators on 3Tej
Validate the rest of an Indian address or identity document with these companion tools:
Frequently asked questions
How does India Post assign the 6 digits of a PIN code?
India Post divides the country into 9 PIN regions numbered 1 through 9. Digit 1 picks the region, digit 2 narrows to a sub-region within that region, digit 3 selects the sorting district where mail is routed, and the last 3 digits identify the specific delivery post office. The structure was introduced on 15 August 1972 by the then Union Communications Minister Shriman Indra Kumar Gujral.
What do the 9 PIN regions cover geographically?
Region 1 covers Delhi, Haryana, Punjab, Himachal Pradesh, Jammu and Kashmir. Region 2 covers Uttar Pradesh and Uttarakhand. Region 3 covers Rajasthan and Gujarat. Region 4 covers Maharashtra, Madhya Pradesh, Chhattisgarh, Goa. Region 5 covers Andhra Pradesh, Karnataka, Telangana. Region 6 covers Tamil Nadu, Kerala, Puducherry, Lakshadweep. Region 7 covers West Bengal, Odisha, North East, Andaman. Region 8 covers Bihar and Jharkhand. Region 9 is reserved for the Army Postal Service (APO and FPO field post).
What does a PIN code like 560001 actually decode to?
560001 starts with 5 (South region: AP, Karnataka, Telangana), the second digit 6 narrows it to the Karnataka sub-region, the third digit 0 marks the Bangalore sorting district, and the last three digits 001 identify Bangalore GPO (the general post office). PIN codes ending in 001 are almost always the head GPO of that sorting district.
Why do some PIN codes begin with 9, and what is APO mail?
PIN codes that begin with 9 belong to the Army Postal Service, which routes mail for Indian Armed Forces personnel posted to field locations, ships, or border deployments where a normal civilian PIN would compromise location secrecy. The actual physical destination is decoded internally by APO sorting centres in Delhi, Mumbai, Chennai, Kolkata and other base post offices, while the visible 9xxxxx code keeps the deployment confidential.
How is a PIN code different from a ZIP code, a postcode, or a postal code?
PIN (Postal Index Number) is India's six-digit system. ZIP (Zone Improvement Plan) is the US system: five digits, or five plus four for ZIP+4. UK postcodes are alphanumeric like SW1A 1AA. Canada uses alphanumeric A1A 1A1. Germany, France, Italy, Spain use 5 digits. The function is identical (route mail to a delivery office) but the encoding differs, so an Indian PIN cannot be cross-validated against a US ZIP regex.
Last updated 2026-05-28.