Anomaly check
Wrong tax head: IGST against CGST+SGST
The total tax is right, the return balances, and the client still ends up paying twice — once in the correct head and once as a refund claim.
Sec. 10 & 12, IGST Act 2017 r/w Sec. 77, CGST Act
Law current as of 21 September 2026
The rule in one line
- The tax head follows the place of supply. An inter-State supply attracts IGST; an intra-State supply attracts CGST plus SGST. The head is not a matter of convenience or of where the invoice was raised.
Where the error comes from
- A billing master with the wrong state code against a customer.
- Bill-to and ship-to in different states, where the place of supply follows the rule for the type of supply rather than the delivery address.
- Services supplied to an unregistered recipient, where the place of supply is determined by the address on record.
- Software defaults that pick the head from the supplier's own state rather than the place of supply.
How to correct it
- Amend the invoice in the next GSTR-1 so the return reports the correct head.
- Pay the correct head, then claim refund of the tax wrongly paid under Sec. 77 of the CGST Act read with Sec. 19 of the IGST Act. Interest is not payable on the correct head in this situation where the conditions are met.
- Correct the customer master so the same invoice series does not repeat the error.
Test this on a real register
Upload a sales or purchase file in the free simulator — no sign-up — and see every finding with the clause it breaches and the rupee impact. In the signed-in workspace, firm owners and admins can reconcile the books and use the approved figures to prepare and file GSTR-1 or GSTR-3B by EVC.