GST Update: Know These Important Changes in GSTR-3B Filing From January 2026

The Goods and Services Tax Network (GSTN) has recently released an advisory on the Interest Collection and Related Enhancements in GSTR-3B. This advisory explains the improvements made in the GSTR-3B filing from the January 2026 period.

The GST Portal has introduced some important changes in GSTR-3B filing starting from the January 2026 tax period. Let us understand the key changes introduced.

New Method for Calculating Interest in GSTR-3B

Starting from January 2026 onwards, the interest in Table 5.1 of the GSTR-3B on the GST portal will be calculated by providing the benefit of the minimum cash balance available in the Electronic Cash Ledger from the due date of filing the GST return until the date of the tax payment as per Rule 88B(1) of the CGST Rules, 2017.

As per the advisory, this new change is applicable to the late returns filed for January 2026. The interest will be auto-filled in GSTR-3B of the February 2026 tax period.

Revised Interest Computation Formula

Here is how the revised interest will be calculated.

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

Auto-Calculated Interest in Table 5.1 Now Non-Editable

As per the advisory, the auto-calculated interest in Table 5.1 can no longer be edited. The taxpayers cannot revise the auto-filled values downward.

However, the upward modification is allowed. The auto-populated interest shows the minimum interest payable by the taxpayers. Taxpayers are required to self-assess their correct interest liability and modify the auto-populated values upward, if needed.

Auto-Population of Tax Liability Breakup in GSTR-3B

The tax liability breakup table captures the supplies related to the previous tax periods that are reported in the current period. From January 2026, the Tax Liability Breakup Table will be auto-populated in GSTR-3B based on the date of documents pertaining to the supplies reported in GSTR-1 / GSTR-1A / IFF or any earlier period and where the tax is paid in the current GSTR-3B.

How to View the Auto-Filled Breakup?

Here is how the taxpayers can view the auto-populated breakup:

Login > GSTR-3B Dashboard > Table 6.1 (Payment of Tax) > Tax Liability Breakup

Flexible Use of ITC in Table 6.1

Starting from January 2026 onwards, the taxpayers can pay IGST using the CGST and SGST ITC in any order if their IGST ITC is fully exhausted.

Interest Collection for Cancelled Taxpayers

If a cancelled GST registration files its last GSTR-3B late, the interest will be charged and collected in GSTR-10, which is the Final Return.

Refer to the Official Advisory for More Information