GST Invoice Guide for Chennai Businesses & Freelancers (2026)

Freelancers and small businesses registered in Tamil Nadu use GST state code 33 as the first two digits of their GSTIN — getting this wrong on an invoice is one of the most common (and most avoidable) compliance mistakes.

GST invoicing basics for Chennai businesses

Any business registered in Tamil Nadu carries the state code 33 as the first two digits of its GSTIN. This single detail decides whether a transaction is treated as intra-state (CGST + SGST) or inter-state (IGST) — and getting it wrong is one of the most common reasons an invoice gets flagged during a client's own GST reconciliation.

What's different about invoicing from Chennai

Chennai's business landscape leans heavily on manufacturing, auto ancillary, and IT, centred around OMR (Old Mahabalipuram Road) and Guindy. auto-ancillary vendors in Chennai commonly invoice manufacturers in other states, so the place-of-supply rule (not just the billing address) decides whether IGST applies

Building a compliant invoice, step by step

1. Confirm your GSTIN begins with 33 (for Tamil Nadu) and double-check the buyer's GSTIN state code too — don't assume it matches their office address.
2. Decide CGST+SGST vs IGST based on the *place of supply*, not just the billing address on the client's letterhead.
3. Use a sequential invoice number series per financial year, as required under GST rules — this matters even more if you invoice several Chennai clients from the same series.
4. Fill in the correct HSN/SAC code for your goods or service category — this is checked more closely for B2B invoices than B2C.
5. Generate the invoice with Utility Hub's free GST Invoice Generator, export to PDF, and keep a static copy — banks and auditors in Chennai routinely ask for a saved copy, not just a shareable link.

When to double-check with a CA

This guide covers the standard GST invoice format used nationwide, including in Tamil Nadu. For anything involving exports, reverse charge, or composition scheme, confirm the specifics with your CA before sending the invoice to a client.

Frequently asked questions