Inter-State vs Intra-State GST: How One Wrong State Code Breaks Tax Logic
How location of supplier, place of supply, SEZ status, bill-to/ship-to and state registrations determine whether an invoice carries IGST or CGST plus SGST.
For broader context, see the GST Law & Practice Hub.
The customer’s state code is only one input. Inter-State or intra-State treatment is decided by comparing the legally determined supplier location and place of supply, subject to statutory deeming rules.
Current-law status: The place-of-supply and inter-State/intra-State classification rules in this article are governed by the IGST Act, 2017 and CGST Act, 2017 as currently amended and in force - this framework is separate from the Income-tax Act, 2025 transition and has not been replaced. Always check for the latest CBIC notifications and circulars before relying on a classification for a specific transaction.
An intra-State supply generally requires the supplier location and place of supply to be in the same State or Union territory, subject to exclusions.
An inter-State supply generally arises where those locations differ and in specified deemed cases such as supplies to or by an SEZ.
Bill-to/ship-to transactions can use a statutory deemed place-of-supply rule for goods.
Separate GST registrations of the same legal entity are distinct persons; branch supplies can be taxable even without external consideration.
What the business should understand
Do not classify a supply as inter-State or intra-State from the customer’s billing address alone. Identify the establishment that ACTUALLY supplies (not just the contracting head office), then apply the statutory place-of-supply rule for that specific transaction type (goods, services, SEZ, bill-to/ship-to). Only after both legs match do you know whether IGST or CGST+SGST is correct - a mismatched state code on the invoice is usually a symptom of skipping this two-step test, not the root cause itself.
- A wrong-head payment (CGST/SGST paid where IGST was due, or vice versa) is not simply correctable by netting one against the other in the return - the law generally requires paying the correct head afresh and separately claiming refund of the wrongly-paid head.
- Distinct-person rules mean a head office and its branches under separate GST registrations can create a taxable supply between them even with zero cash changing hands - a purely internal cost allocation is not automatically outside GST’s scope.
- SEZ supplies are deemed inter-State by statute regardless of the SEZ unit’s actual physical state - do not apply the ordinary same-state/different-state test to SEZ transactions.
- Keep the e-invoice/e-way bill state codes, the underlying contract’s performing establishment, and the actual goods-movement or service-performance evidence all pointing to the same conclusion - a portal-level match between documents is not proof the underlying classification itself is correct.
Use the Finin2min GST Services Rate Master to apply these points to your figures or facts.
The five-point review
| Check | What to examine |
|---|---|
| Supplier location | Which establishment most directly supplies. |
| Place of supply | Goods movement, delivery, installation or service rule. |
| Recipient | GSTIN and actual contracting establishment. |
| Special status | SEZ, import, export, territorial waters or bill-to/ship-to. |
| Document | State code, tax head and e-invoice/e-way consistency. |
For the connected rule, example or next step, see GST Registration for Multi-State Consulting Businesses.
Practical example
A Maharashtra head office contracts with a customer’s Gujarat GSTIN, but a Tamil Nadu branch actually performs and invoices the service. The supplier location cannot be assumed from the head-office contract; the establishment most directly concerned must be analysed.
How to apply the framework
Maintain a state-code matrix for customers, vendors, branches, warehouses and SEZ units. Require tax approval for transactions where contracting, delivery and billing states differ.
Reconcile wrong-tax corrections to electronic ledgers and customer ITC. A credit note alone may not eliminate the tax paid under the wrong head.
Decision workflow
Define the legal question before changing the return
Identify the GSTIN, tax period, transaction, document and exact statutory question. Review supplier location, place of supply and recipient together. Freeze the source data so that later ERP edits do not destroy the evidence used for the decision.
Reconcile from commercial reality to portal data
Start with the contract or commercial event. Move through the invoice, receipt or movement evidence, e-invoice or e-way bill, accounting entry, return and electronic ledger. Classify each difference as timing, error, ineligible amount, statutory exception, disputed position or completed correction. Avoid a plug entry whose only purpose is to make two reports equal.
Record the conclusion and future control
Prepare a concise position note with facts, authority, amount, alternative view and approval. Preserve the filing acknowledgement and update the responsible master data, vendor rule, invoice workflow or monthly checklist. The objective is not only to survive one review but to prevent the same issue in the next period.
Action checklist
- Identify the supplying establishment.
- Determine the statutory place of supply.
- Check SEZ and deemed inter-State rules.
- Validate recipient GSTIN.
- Generate the correct tax head.
- Document and remediate wrong-head cases.
Evidence to keep
- Contracts and branch responsibility
- Goods movement or service-performance evidence
- Recipient and SEZ documents
- Invoice/e-invoice/e-way records
- Wrong-head payment and refund file
Warning signs
- State code selected from mailing address
- Head office treated as supplier for every branch
- SEZ supply billed intra-State
- Bill-to/ship-to rule ignored
- CGST/SGST simply netted against IGST
Finin2min takeaway
GST positions are strongest when the transaction, legal provision, invoice, physical or service evidence, books, return and electronic ledger agree. A portal match without commercial evidence is not a complete control.
For the connected rule, example or next step, see GST Place of Supply for Multi-State Consulting.
Frequently Asked Questions
Source and review trail
Use the current official instrument, portal or regulator publication before acting. This panel separates the category authority from page-specific references.
- Primary category
- GST & Indirect Tax
- Official starting point
- www.gst.gov.in
See “Official References” above for the IGST Act, CGST Rules 2017, Sectoral GST FAQs and CGST Act 2017 references used in this article.
Additional source links
For the connected rule, example or next step, see GST HSN/SAC Code Selection for Small Businesses: Examples, Documents and Common Mistakes.