GSTR-3B is the summary GST return where you declare total outward liability, claim input tax credit, and pay the net tax — monthly for most businesses, quarterly under QRMP. As of Aug 2026 the outward liability figures are auto-populated from GSTR-1 and hard-locked: you cannot edit them in GSTR-3B, and corrections must go through GSTR-1A before filing.
The return has two working parts: liability (pulled from your GSTR-1) and ITC (drawn from GSTR-2B, which in turn reflects your Invoice Management System actions). You settle the net amount from your electronic cash and credit ledgers and file — monthly filers generally by the 20th of the following month, QRMP filers by the 22nd or 24th depending on state. A nil return is still a return; skipping it accrues late fees per day.
The practical workflow for an owner: between the 12th and the 20th, reconcile purchases against GSTR-2B, act on IMS invoices, verify the auto-locked liability matches your books, and fix any GSTR-1 error via GSTR-1A before touching GSTR-3B. Paying late attracts interest on the cash portion of the liability, so the reconciliation has to finish before the due date, not after.
Non-filing snowballs fast: two consecutive missed periods can block e-way bill generation, and continued default invites suspension through REG-31. And since November 2025 the three-year bar applies — a GSTR-3B more than three years past its due date can never be filed, which permanently forfeits the ITC sitting in that period.
Act on it
Reviewed to the law in force in FY 2026-27. General information, not advice — confirm the position for your facts before acting.