Short answer: GSTR-1 is the statement of your outward supplies (sales), invoice by invoice for B2B and in summary for B2C. GSTR-3B is the monthly or quarterly summary return in which you declare the tax payable, claim input tax credit and pay the balance in cash. GSTR-1 is due on the 11th of the next month (13th after the quarter for QRMP); GSTR-3B is due on the 20th (22nd or 24th after the quarter for QRMP).
Side by side
| GSTR-1 | GSTR-3B | |
|---|---|---|
| What it is | Details of outward supplies | Summary return with tax payment |
| Contents | B2B invoices, B2C sales, exports, credit/debit notes, HSN summary, documents issued, e-commerce supplies | Total outward supplies, ITC claimed, ITC reversed, tax paid in cash and by credit |
| Monthly due date | 11th of next month | 20th of next month |
| QRMP due date | 13th of the month after the quarter (IFF optional for B2B in months 1 and 2, by the 13th) | 22nd or 24th of the month after the quarter, depending on the state; tax for months 1 and 2 by PMT-06 by the 25th |
| Effect on buyer | Your B2B invoices appear in the buyer's GSTR-2B, so they can claim ITC | None directly |
How they link
The tax liability in GSTR-3B is auto-filled from your GSTR-1. If you made a mistake in GSTR-1, correct it through GSTR-1A or in a later GSTR-1, not by changing the auto-filled figures. Your input tax credit in GSTR-3B is auto-filled from GSTR-2B, which comes from your suppliers' GSTR-1.
Late fee and interest
- Late fee: ₹50 per day (₹25 CGST + ₹25 SGST), or ₹20 per day for a nil return, subject to caps that depend on turnover.
- Interest: 18% a year on the tax paid late in cash (net of eligible ITC).
- Three-year limit: the GST portal does not accept a GSTR-1 or GSTR-3B after three years from its due date.
Example
A monthly filer's October 2026 return: GSTR-1 by 11 November 2026, then GSTR-3B by 20 November 2026. A QRMP filer for October–December 2026: GSTR-1 by 13 January 2027 and GSTR-3B by 22 or 24 January 2027, with PMT-06 payments for October and November by 25 November and 25 December.
Frequently asked questions
Can I file GSTR-3B before GSTR-1?
The portal allows it, but the liability in GSTR-3B is auto-filled from GSTR-1, so file GSTR-1 first to avoid mismatches.
Who can choose QRMP?
A registered person with aggregate turnover up to ₹5 crore in the previous financial year can opt for quarterly filing under QRMP.
Do I file GSTR-1 if there were no sales?
Yes. A nil GSTR-1 must be filed, which can also be done by SMS.
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Official sources
Rules on this page come from these official government sources. Check them for the latest position.
More guides
GST invoice format
Every field a GST tax invoice must have (rule 46), copies, time limits and e-invoicing.
Credit note and debit note in GST
When to issue each (section 34), the time limit, the fields and how to report them in GSTR-1.
HSN code rules
How many HSN digits you must write by turnover, SAC for services and the GSTR-1 HSN summary.
Last updated: 7 November 2026. Published by S Jha Legal Sansar & Associates. Rules as applicable for FY 2026-27; laws change, so check the official source before you act. Editorial policy · Disclaimer