CGST, SGST and IGST: How to Review the Tax Type on an Invoice

Review CGST, SGST and IGST by determining the supplier location, the place of supply and the statutory nature of the transaction. Ordinary intra-State taxable supplies generally attract CGST plus SGST, while inter-State taxable supplies generally attract IGST. Union territory transactions can involve UTGST instead of SGST. The IGST Act contains exceptions, so comparing two address fields is only the beginning of the review.

Establish which registration is supplying

A business operating in several States should identify the GSTIN making the supply before selecting tax heads. The invoice's issuing address, stock location and contracting establishment need to reflect the actual arrangement. A common group bank account does not tell you which registration supplies the goods or services.

For example, a company may have a warehouse in Ahmedabad and a sales office in Mumbai. Do not choose Maharashtra simply because the quotation carries the Mumbai office letterhead. Review the order, dispatch and registration records. The supplying registration is a factual input to the tax analysis, not a formatting preference.

Determine place of supply under the relevant rule

Goods involving movement, bill-to/ship-to directions and installation can produce different place-of-supply questions. Goods supplied to unregistered persons have a specific provision under section 10(1)(ca), including the address treatment clarified by CBIC Circular 209/3/2024-GST. Services require their own framework and specific-category checks.

Keep a short record of the basis for unusual supplies. It can state the purchasing registration, delivery or service location, rule considered and conclusion. This is more useful than a generic approval that says “IGST applicable” without identifying why. Repeat supplies can reuse an approved analysis only while the relevant facts remain the same.

Compare two illustrative calculations

Assume a confirmed 18% aggregate rate and taxable value of ₹45,000. For an ordinary intra-State supply in a State, CGST at 9% is ₹4,050 and SGST at 9% is ₹4,050. Total tax is ₹8,100 and invoice total is ₹53,100.

For an ordinary inter-State supply at the same aggregate rate and value, IGST at 18% is ₹8,100. The invoice total remains ₹53,100. Identical totals can therefore hide a serious tax-head error. A review based only on the amount payable will not detect whether the wrong components were used.

The assumed rate is for arithmetic only. Classification, exemptions, reverse charge and any special rate conditions still need confirmation for the actual supply.

Watch the exceptions to same-State logic

Supplies to or by an SEZ unit or developer are treated as inter-State under the IGST framework, even when locations are within the same State. Separately, zero-rated treatment for supplies to an SEZ depends on the applicable authorised-operations conditions and route. Do not turn the inter-State classification alone into an automatic refund or exemption conclusion.

Cross-border transactions and imports also require specific analysis. A foreign customer's name on an invoice does not establish that all export-of-service conditions are met. Likewise, a delivery inside India does not by itself answer every import or bill-to/ship-to question. Escalate the facts that fall outside the routine domestic workflow.

Review tax heads independently of collection mode

Cash, UPI, card and bank transfer are payment methods. None independently selects CGST/SGST or IGST. A retail sale to an unregistered customer still needs the correct place-of-supply treatment. The absence of a GSTIN does not make a taxable supply tax-free or invariably local.

Customer requests also need checking. If a purchaser says “charge IGST so we can claim credit,” obtain the relevant registration and supply facts. The desired accounting outcome cannot override the statute. Explain the document basis clearly so that sales staff do not change tax heads solely to clear a payment hold.

Find errors before the return process

Use exception checks for invoices whose tax heads disagree with the approved place-of-supply conclusion, supplies to SEZ customers showing ordinary local components and manual changes made after invoice approval. Check that tax amounts in the printed invoice, ledger and applicable electronic invoice data match.

For invoices with several rates, verify each rate group under the selected heads. An invoice can have correct IGST on one line and an accidental CGST/SGST default on another. The grand total may still look plausible, particularly where rates are equal. A structured line review catches what a total-only check misses.

Include tax-head review in credit and debit note preparation. A later adjustment should link to the underlying supply and use the approved treatment, with separate review where the original invoice was wrong. Do not let the customer's current address overwrite the historical supply facts when generating an adjustment from today's master data.

Correct the underlying decision, not just the label

When an issued invoice uses the wrong head, preserve the original and investigate the reporting and payment position before choosing a correction route. Changing “CGST” to “IGST” on a PDF does not move tax already recorded or paid. Document the reason, customer communication and corresponding accounting or return action.

A dependable process makes tax-head selection the outcome of a short, evidence-based decision. Identify the supplier, determine place of supply, review statutory exceptions and calculate the components. That order prevents an address shortcut or customer request from becoming an unsupported invoice tax treatment.