GSTR-1 Due Date

What GSTR-1 actually reports

GSTR-1 is the outward-supplies return — it reports invoice-level details of every sale, credit note, and debit note issued during the period. Unlike GSTR-3B, no tax is paid through GSTR-1 itself; its purpose is to feed the recipient's input tax credit, which becomes visible in their auto-drafted GSTR-2B shortly after filing.

Because GSTR-2B generation depends on GSTR-1 being filed, filing it even a day late can delay every one of your customers' ITC claims for the period — a knock-on effect that doesn't show up in your own compliance record but genuinely affects business relationships.

Monthly vs QRMP due dates

Regular monthly filers must file GSTR-1 by the 11th of the following month — a full nine days before GSTR-3B's 20th deadline for the same period, by design, so GSTR-3B's auto-populated figures can reflect the corresponding GSTR-1 data. QRMP filers, by contrast, file GSTR-1 only once a quarter, due by the 13th of the month following the quarter's end — but can optionally use the Invoice Furnishing Facility (IFF) in the first two months of the quarter to upload B2B invoices early, so their buyers aren't stuck waiting a full quarter for ITC visibility.