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GSTR-1 vs GSTR-3B: Differences, Due Dates & Late Fees

The two returns every regular taxpayer files each month — what goes in each, when, and what it costs if you miss the date.

30 May 2026 7 min readBy SmartGST Team
GSTR-1 vs GSTR-3B: Differences, Due Dates & Late Fees

GSTR-1

A statement of all outward supplies (sales) — B2B invoice-wise, B2C summary, credit/debit notes, exports and HSN summary. Due on the 11th of the following month (13th for QRMP quarterly filers).

GSTR-3B

A self-declared summary return where you report total sales, ITC claimed and pay the net tax. Due on the 20th of the next month (22nd/24th for QRMP depending on state).

Late fees

₹50 per day (₹20 for nil returns) capped based on turnover, plus 18% interest on late tax payment. GSTR-1 not filed also blocks your GSTR-3B.

Reconciliation is key

Your GSTR-3B liability must match GSTR-1; ITC in 3B should match GSTR-2B. Mismatches trigger DRC-01B/01C notices.

One-click summaries

SmartGST's GST Filing page produces GSTR-1 tables and a 3B summary from your invoices and purchase bills, exportable as Excel, CSV or PDF for your CA.

Try it on your next invoice

SmartGST Invoices automates GST calculation, HSN codes, reminders and GSTR reports. Free to start.

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Keywords: gstr 1 due date · gstr 3b late fee. This article is general information, not professional tax advice.