GSTR-1, GSTR-3B and the GST Return Cycle, Explained

The two returns that matter most

For most regular taxpayers, GST filing comes down to two returns each period. GSTR-1 reports the details of your outward supplies — your sales invoices. GSTR-3B is the summary return where you declare your total sales, claim input tax credit, and pay the net tax.

Think of GSTR-1 as the detailed sales statement and GSTR-3B as the summary-and-payment return. They must tell a consistent story; when they do not, the department notices.

Due dates

For monthly filers, GSTR-1 is generally due by the 11th and GSTR-3B by the 20th of the following month. Businesses under the QRMP scheme file GSTR-1 and GSTR-3B quarterly, while still paying tax monthly through a simple challan.

The QRMP scheme

Quarterly Return, Monthly Payment (QRMP) is available to smaller taxpayers below a turnover limit. You file the two returns once a quarter but pay tax monthly. It reduces filing frequency without letting your tax payments pile up.

Nil returns are still mandatory

One of the most common and expensive mistakes is skipping a return because there were no sales. Even a Nil return must be filed. If you miss it, a late fee accrues per day until you file — so a few forgotten Nil returns can quietly become a real bill.

Why mismatches trigger notices

The department cross-checks. If your GSTR-1 sales do not match your GSTR-3B summary, or if the input tax credit you claim in GSTR-3B exceeds what appears in your auto-drafted GSTR-2B, you can expect a mismatch notice. This is why reconciliation before filing is not optional — it is what keeps notices away.