GSTR-1 and GSTR-3B are the two returns almost every regular GST taxpayer files. They are linked: since July 2025, mistakes in GSTR-1 flow into GSTR-3B and can't be fixed there. Here is how they differ, when they are due and how to keep them consistent.
GSTR-1 vs GSTR-3B at a glance
| GSTR-1 | GSTR-3B | |
|---|---|---|
| What it is | Statement of outward supplies (sales) | Summary return of sales, input tax credit and tax payment |
| Level of detail | Invoice-wise for B2B; summary for most B2C; HSN-wise summary; credit/debit notes | Totals only |
| Tax payment | No payment | Tax is paid with this return |
| Input tax credit | Not claimed here | ITC is claimed here, based on GSTR-2B |
| Effect on buyers | Your B2B invoices appear in your buyers' GSTR-2B | No direct effect |
| Monthly due date | 11th of the next month | 20th of the next month |
| QRMP due date | 13th of the month after the quarter (IFF optional for months 1–2) | 22nd or 24th of the month after the quarter, depending on state |
How the two returns are linked
When you file GSTR-1 (or IFF), the GST portal auto-populates your tax liability in GSTR-3B. From the July 2025 tax period, this auto-populated liability can no longer be edited in GSTR-3B, and from the November 2025 period Table 3.2 (inter-state supplies to unregistered persons, composition taxpayers and UIN holders) is locked too. If something in GSTR-1 was wrong, you correct it through GSTR-1A, an optional amendment form available after filing GSTR-1 and before filing GSTR-3B for the same period. Input tax credit is not locked. For what exactly is locked, with the GSTN advisory for each date, see GSTR-3B lock and the three-year time bar.
On the input side, your GSTR-2B, a static statement generated around the 14th of each month from your suppliers' filings, shows the credit available to you. Claim ITC in GSTR-3B based on GSTR-2B and your purchase records.
The QRMP scheme
Taxpayers with aggregate turnover up to ₹5 crore can opt for the Quarterly Return Monthly Payment (QRMP) scheme. They file GSTR-1 and GSTR-3B quarterly, can upload B2B invoices monthly through the Invoice Furnishing Facility (IFF) so buyers get credit sooner, and pay tax monthly through form PMT-06 by the 25th for the first two months of the quarter.
Late fees, interest and the three-year limit
- Late fee: generally ₹50 per day (₹25 CGST + ₹25 SGST), or ₹20 per day for nil returns, capped based on turnover. Check the current notifications for the caps that apply to you.
- Interest: 18% per year on tax paid late, calculated on the net cash liability.
- Three-year time bar: a return can't be filed more than three years after its due date. The GST portal enforces this from the November 2025 tax period (for example, GSTR-1 and GSTR-3B for October 2022 were barred from 1 December 2025).
- Sequential filing: GSTR-3B can't be filed if earlier returns are pending, and a missed GSTR-1 blocks the next one.
Common mistakes and how to avoid them
| Mistake | Effect | How to avoid |
|---|---|---|
| Wrong buyer GSTIN on a B2B invoice | Buyer can't see the credit; you face disputes | Validate GSTIN when creating the customer |
| B2B sale reported as B2C | Buyer loses ITC | Always capture the GSTIN for registered buyers |
| Wrong GST rate or HSN after GST 2.0 | Liability in GSTR-1 and 3B is wrong | Update item rates in your billing software |
| Credit notes not reported | You pay tax on sales that were returned | Record returns as credit notes in the same period |
| Claiming ITC not in GSTR-2B | Notices and interest | Reconcile purchases with GSTR-2B monthly |
| Filing GSTR-3B before checking GSTR-1 | Locked liability is wrong | Use GSTR-1A to correct before filing 3B |
A simple monthly routine
- Record all sales as GST invoices and all purchases as they arrive.
- By the 10th, review sales: customer GSTINs, HSN codes, rates and credit notes.
- File GSTR-1 by the 11th (or IFF/quarterly GSTR-1 under QRMP).
- Around the 14th, compare GSTR-2B with your purchase records.
- Check the auto-populated GSTR-3B, correct via GSTR-1A if needed, pay tax and file by the 20th.
How VelBooks helps
Because every sale is a GST invoice in VelBooks with GSTIN, HSN and tax split, your GSTR-1 data is ready when you need it. GSTR filing and return management works from the same data, so your books, GSTR-1 and GSTR-3B tell the same story.
Sources
- GST portal
- GSTN: auto-populated liability in GSTR-3B non-editable from July 2025
- GSTN: Table 3.2 of GSTR-3B non-editable from November 2025
- GSTN: returns barred after three years (29 Oct 2025)
- CBIC
This article is general information, not legal or tax advice. Rules change; check the official sources above or consult your tax adviser.