Understanding GSTIN Structure
The Goods and Services Tax Identification Number (GSTIN) is a unique 15-digit alphanumeric code assigned to every taxpayer registered under GST. This number serves as the primary identifier for all GST-related transactions and compliance activities.
GSTIN Format Breakdown
A GSTIN follows a specific 15-character structure:
Format: XX-XXXXXXXXXX-X-X
- Position 1-2: State Code (01-37)
- Position 3-12: PAN of the taxpayer (10 characters)
- Position 13: Entity Number (1-9, A-Z)
- Position 14: Default 'Z' (reserved for future use)
- Position 15: Check digit for validation
State Code Mapping (Complete List)
| Code |
State/UT Name |
Code |
State/UT Name |
| 01 | Jammu & Kashmir |
02 | Himachal Pradesh |
| 03 | Punjab |
04 | Chandigarh |
| 05 | Uttarakhand |
06 | Haryana |
| 07 | Delhi |
08 | Rajasthan |
| 09 | Uttar Pradesh |
10 | Bihar |
| 11 | Sikkim |
12 | Arunachal Pradesh |
| 13 | Nagaland |
14 | Manipur |
| 15 | Mizoram |
16 | Tripura |
| 17 | Meghalaya |
18 | Assam |
| 19 | West Bengal |
20 | Jharkhand |
| 21 | Odisha |
22 | Chhattisgarh |
| 23 | Madhya Pradesh |
24 | Gujarat |
| 26 | Dadra & Nagar Haveli and Daman & Diu |
27 | Maharashtra |
| 29 | Karnataka |
30 | Goa |
| 31 | Lakshadweep |
32 | Kerala |
| 33 | Tamil Nadu |
34 | Puducherry |
| 35 | Andaman & Nicobar |
36 | Telangana |
| 37 | Andhra Pradesh |
38 | Ladakh |
| 97 | Other Territory |
99 | Centre Jurisdiction |
PAN Structure in GSTIN
The PAN (Permanent Account Number) embedded in GSTIN follows this pattern:
- Characters 1-3: Three alphabetic characters (sequence of letters AAA to ZZZ)
- Character 4: Entity type identifier
- C = Company
- P = Person (Individual)
- H = HUF (Hindu Undivided Family)
- F = Firm/Partnership
- A = AOP (Association of Persons)
- T = Trust
- B = BOI (Body of Individuals)
- L = Local Authority
- J = Artificial Juridical Person
- G = Government
- Character 5: First character of surname/name
- Characters 6-9: Four numeric characters (sequential from 0001 to 9999)
- Character 10: Alphabetic check digit
Entity Number Significance
The 13th character (Entity Number) indicates:
- 1-9: Single registration for a PAN (most common)
- A-Z: Multiple registrations under same PAN (for businesses with multiple places of business in same state)
Example: If a business has 3 registrations in Maharashtra under same PAN, they'll have entity numbers 1, 2, and 3.
Check Digit Calculation
The 15th character is a check digit calculated using the Luhn algorithm (modulus 10) applied to the first 14 characters. This ensures data integrity and helps detect errors in GSTIN entry.
Validation Rules:
- ✓ Total length must be exactly 15 characters
- ✓ First 2 digits must be valid state code (01-38, 97, 99)
- ✓ Next 10 characters must be valid PAN format
- ✓ 13th character must be alphanumeric (1-9, A-Z)
- ✓ 14th character must be 'Z'
- ✓ 15th character must match calculated check digit
Common GSTIN Validation Errors
- Incorrect Length: GSTIN must be exactly 15 characters
- Invalid State Code: First 2 digits must correspond to a valid state
- Wrong PAN Format: Characters 3-12 must follow PAN structure
- Missing 'Z': 14th position must always be 'Z'
- Check Digit Mismatch: Last character doesn't match calculated value
- Special Characters: Only alphanumeric characters allowed
How to Use This Checker
- Enter the 15-digit GSTIN in the input field
- The tool performs real-time format validation
- Click "Validate & Decode" to see detailed breakdown
- Review state, PAN, entity type, and check digit status
- Use sample GSTINs provided to understand the structure
Important Notes
- This tool validates GSTIN format and structure only
- For official registration status, visit GST Portal (gst.gov.in)
- Active/Cancelled status requires GST Portal API access
- Use this tool to verify GSTIN before business transactions
- All validations are performed client-side (no data sent to server)
Frequently Asked Questions
What is GSTIN and why is it important?
GSTIN (GST Identification Number) is a unique 15-digit code assigned to every taxpayer registered under GST. It's important because:
- Required for filing GST returns and paying taxes
- Needed for issuing GST-compliant invoices
- Used for claiming Input Tax Credit (ITC)
- Mandatory for inter-state transactions
- Serves as proof of GST registration
How can I verify if a GSTIN is active or cancelled?
To check active/cancelled status of GSTIN:
- Visit the official GST Portal at gst.gov.in
- Go to "Search Taxpayer" under Services section
- Enter the GSTIN and Captcha
- View registration status, business name, and registration date
This tool validates format only. For official status, always use GST Portal.
What does each part of GSTIN represent?
GSTIN structure (15 characters):
- Digits 1-2: State code where business is registered (01-38)
- Digits 3-12: PAN (Permanent Account Number) of the taxpayer
- Digit 13: Entity number (registration sequence for same PAN)
- Digit 14: Default 'Z' (reserved for future use)
- Digit 15: Check digit calculated using modulus algorithm
Can one PAN have multiple GSTINs?
Yes, a single PAN can have multiple GSTINs in the following scenarios:
- Multiple states: Separate GSTIN for each state where business operates
- Multiple registrations in same state: Entity number (13th digit) changes (1, 2, 3, etc.)
- Multiple business verticals: Different GSTINs for different business types
Example: Maharashtra (27) + Same PAN + Entity 1, 2, 3 = Three different GSTINs
What does the 4th character in GSTIN indicate?
The 4th character is part of PAN and indicates entity type:
- C: Company (Private/Public Limited, Section 8)
- P: Person (Individual/Proprietor)
- H: Hindu Undivided Family (HUF)
- F: Firm/Partnership
- A: Association of Persons (AOP)
- T: Trust (Charitable/Religious)
- B: Body of Individuals (BOI)
- L: Local Authority
- J: Artificial Juridical Person
- G: Government
Is GSTIN same as TIN or VAT number?
No, GSTIN is different from TIN (Tax Identification Number) and VAT number:
- TIN/VAT: Used under old indirect tax regime (pre-GST)
- GSTIN: Unified number under GST (from July 2017 onwards)
- Existing VAT/TIN holders were migrated to GST and issued GSTIN
- GSTIN is 15 digits, while TIN was typically 11 digits
- GSTIN includes PAN, which TIN didn't
How do I get a GSTIN for my business?
To obtain GSTIN, follow these steps:
- Check if GST registration is mandatory for your turnover
- Visit gst.gov.in and click "Register Now"
- Choose "New Registration" and taxpayer type
- Enter PAN, mobile number, and email (OTP verification)
- Fill Part A with basic business details
- Submit documents (PAN, address proof, bank details, photos)
- Complete Part B with detailed business information
- ARN (Application Reference Number) generated
- GST officer verifies and approves within 7 days
- GSTIN certificate issued via email
Can GSTIN be cancelled or surrendered?
Yes, GSTIN can be cancelled in following scenarios:
- Voluntary cancellation: When business discontinues or falls below threshold
- Automatic cancellation: For non-filing of returns for 6 months
- Official cancellation: By GST department for violations
- Death of proprietor: Legal representative must apply
Apply online through GST Portal → Services → Registration → Application for Cancellation of Registration
What happens if I enter wrong GSTIN in invoice?
Consequences of wrong GSTIN on invoice:
- Buyer cannot claim Input Tax Credit (ITC)
- Invoice becomes invalid for GST purposes
- Mismatch in GSTR-2A/2B for buyer
- Potential penalty for issuing incorrect invoice
- Need to issue revised invoice or credit note
Prevention: Always verify GSTIN using tools like this before issuing invoices!
Is GST registration mandatory for all businesses?
GST registration is mandatory if:
- Annual turnover exceeds ₹40 lakhs (₹20 lakhs for special category states)
- Making inter-state supplies (any turnover)
- Casual taxable person or non-resident taxable person
- Required to pay GST under reverse charge
- E-commerce operator or supplier through e-commerce
- Input Service Distributor
- Aggregator (taxi services, delivery, etc.)
Composition scheme: ₹1.5 crore threshold (₹75 lakhs for special states)