Understanding State Codes in the 15-Digit GSTIN Format

Have you ever wondered why every GST number in Maharashtra starts with 27, while every number in Delhi starts with 07? The Indian Goods and Services Tax Identification Number (GSTIN) is not just a random string of 15 characters; it is a highly structured code.

Decoding this code is crucial for businesses, especially when determining whether to charge CGST/SGST (intra-state) or IGST (inter-state) on an invoice. You can decode and verify any GST number instantly using our GSTIN Validator.

The Role of the First Two Digits

The first two digits of a 15-digit GSTIN represent the State Code as defined under the Indian Census of 2011. Since GST is a destination-based tax, knowing the supplier’s and the recipient’s state is fundamental to compliance.

If your business is located in Karnataka (State Code 29) and your buyer’s GSTIN also starts with 29, the transaction is intra-state. You must charge CGST and SGST. If the buyer’s GSTIN starts with 33 (Tamil Nadu), the transaction is inter-state, and you must charge IGST.

(If you are unsure of the exact tax split amounts, use our GST Calculator to get instant figures).

Common GST State Codes

Here is a quick reference for some of the most common state codes in India:

• 07 - Delhi
• 09 - Uttar Pradesh
• 19 - West Bengal
• 24 - Gujarat
• 27 - Maharashtra
• 29 - Karnataka
• 33 - Tamil Nadu
• 36 - Telangana

Why State Code Mismatches are Red Flags

When verifying a new vendor’s invoice, always look at the address printed on the bill and compare it to the GSTIN. If a vendor provides an invoice with an address in Mumbai, Maharashtra, but their GSTIN starts with 09 (Uttar Pradesh), do not process the payment immediately. This is a major red flag for potential tax fraud.

To perform a thorough check:

1. Enter the number into our GSTIN Validator.
2. The tool will mathematically verify the checksum and instantly display the associated state name.
3. If the state does not match the billing address, contact the vendor for clarification.

Complete the Verification Loop

Checking the state code is just one part of due diligence. You must also ensure the embedded PAN (characters 3 to 12) matches the vendor’s legal identity. Furthermore, before claiming Input Tax Credit, always verify the active status of the registration on the official GST Portal.

By integrating a quick GSTIN validation into your accounting workflow, you protect your business from compliance headaches and ensure your GST Return Due Dates are met without ITC reversals.