The GSTN has issued an Advisory dated 30.01.2026, informing taxpayers about important system-level enhancements in GSTR-3B, effective from the January-2026 tax period onwards. These changes primarily relate to interest computation, auto-population of tax liability breakup, cross-utilization of ITC, and interest recovery in final return (GSTR-10).

The Advisory clarifies that – 

• Interest on delayed GSTR-3B will now be auto-calculated after giving credit for the minimum cash balance available in the Electronic Cash Ledger from the due date till payment date, as per Rule 88B and proviso to Section 50. The auto-populated interest is the minimum payable amount and cannot be reduced, though it may be increased by the taxpayer if required.
• The tax liability breakup table in GSTR-3B will be auto-populated based on the document dates of supplies reported in earlier periods (GSTR-1 / GSTR-1A / IFF) but paid in the current return, ensuring accurate period-wise reporting.
• Once IGST ITC is exhausted, the portal will allow flexible cross-utilisation of CGST and SGST ITC towards IGST liability.
• For cancelled registrations, interest on delayed filing of the last GSTR-3B will be collected through GSTR-10 (Final Return).

The complete Advisory can be accessed at https://tutorial.gst.gov.in/downloads/news/advisory_on_interest_calculator.pdf