Changes In Interest Calculation For GST Monthly Return From January 2026; GSTN Issues Advisory

The Goods and Services Tax Network (GSTN) has issued an advisory setting out changes to interest computation and related system features in the monthly return GSTR-3B (GST). The changes will apply from the January 2026 tax period onwards. 

From January 2026, interest shown in Table 5.1 of GSTR-3B (GST) will be calculated after adjusting the minimum cash balance available in the Electronic Cash Ledger from the due date of filing until the date of tax payment. The change follows the proviso to Rule 88B(1) of the CGST Rules, 2017. Interest will be worked out on the net tax liability for the period of delay.

GSTN has clarified that the interest auto-populated by the system cannot be reduced. It represents the minimum interest payable. Taxpayers may increase the amount after self-assessing their actual liability.

The revised computation will apply to delayed monthly returns for January 2026. In such cases, interest will be auto-populated in the GSTR-3B filed for February 2026.

GSTN has also enabled auto-population of the tax liability breakup table in the monthly return GSTR-3B (GST), based on supply documents reported in GSTR-1, GSTR-1A, or the Invoice Furnishing Facility for earlier periods, where tax is paid in the current return.