GSTN Advisory: Key Changes in GSTR-3B from January 2026

The GST portal has recently made some important changes for the registered taxpayers filing GSTR-3B. The Goods and Services Tax Network (GSTN) has issued an advisory announcing the improvements made in the GSTR-3B filing from the January 2026 period.

Updated Interest Calculation

From the January 2026 tax period onwards, interest in Table 5.1 of GSTR-3B will be calculated using a revised formula. The system will now consider the minimum balance available in the Electronic Cash Ledger (ECL) from the due date of filing till the date of tax payment in accordance with Rule 88B(1) of the CGST Rules, 2017.

Here is the new formula for calculating interest:

Interest = (Net Tax Liability – Minimum Cash Balance in ECL from due date to date of debit) × (No. of days delayed / 365) × Applicable Interest Rate

This change applies to the delayed returns filed for the January 2026 tax period, for which interest shall be auto-populated in the February 26 tax period’s GSTR-3B.

Auto-Population of Tax Liability Breakup

The “Tax Liability Breakup Table” in GSTR-3B will now be auto-populated based on the date of documents related to the supplies reported in GSTR-1, GSTR-1A, or IFF for the previous tax period and where the tax is paid in the current return. This table captures supplies of previous tax periods reported in the current period.

Interest Auto-Population in Table 5.1

As per the advisory, the system-computed interest in Table 5.1 will be non-editable. Auto-populated values are suggestive in nature. Taxpayers can make upward modifications based on their records and computations, if required. However, downward modification is not allowed.

Taxpayers can view the auto-populated breakup at Login → GSTR-3B Dashboard → Table 6.1 (Payment of Tax) → Tax Liability Breakup.

ITC Cross-Utilisation

Once the IGST Input Tax Credit (ITC) is fully used, taxpayers can now use CGST and SGST ITC to pay IGST liability in any order.

Interest in GSTR-10

For cancelled registrations, if the last GSTR-3B is filed late, interest will be collected through GSTR-10, which is the final return.