C.K. GuptaEvery registered GST taxpayer deals with two returns month after month: GSTR-1 and GSTR-3B. They look similar on paper but do very different jobs. Understanding the difference protects you from late fees, blocked input credit and unhappy buyers.
Simple version: GSTR-1 tells the government what you sold, invoice by invoice. GSTR-3B pays the government the net tax after setting off input credit.
Side-by-side comparison
| Point | GSTR-1 | GSTR-3B |
|---|---|---|
| What it contains | Invoice-wise outward supplies (sales), HSN summary, documents issued | Summary of sales, ITC claimed, and tax paid in cash/credit |
| Who sees it | Your buyers — it feeds their GSTR-2B (input credit view) | Only the tax department |
| Tax payment | No payment — data only | Yes — this is where GST is actually paid |
| Due date (monthly filing) | 11th of the following month | 20th of the following month |
| Due date (QRMP quarterly) | 13th of the month after the quarter ends | 22nd or 24th after quarter end (depends on your state) |
| Late fee (from July 2023) | ₹50/day (₹20/day for nil returns), capped at ₹5,000 (₹500 for nil) | Same structure — ₹50/day, ₹20/day nil, caps apply |
Late fee is split between CGST and SGST equally (or CGST + UTGST in union territories). Interest at 18% per year applies on tax paid late through GSTR-3B — the interest clock runs from the due date even if you file later.
Why the order matters
Always file GSTR-1 before GSTR-3B. Your GSTR-1 data flows into each buyer’s GSTR-2B. A buyer can claim input credit only for invoices that appear there. If your GSTR-3B shows a sale that never reached GSTR-1 correctly, the buyer’s credit can be denied and they will come back to you for the money.
Example
You issue an invoice of ₹1,18,000 (18% GST) to a company client on 5 August. If you file GSTR-1 for August but accidentally skip that invoice, your client’s September GSTR-2B will not show it — their ₹18,000 credit is blocked until you correct GSTR-1 or they adjust your payment. Getting GSTR-1 right the first time avoids all of that.
Five mistakes that cost businesses real money
- Wrong GSTIN on invoices — the invoice lands in no one’s GSTR-2B. Verify every new client’s GSTIN on the portal before the first bill.
- Selling under the wrong HSN / description — invites rate and classification mismatches during audit.
- Claiming ITC in GSTR-3B before it appears in GSTR-2B — Section 16(2)(aa) requires the invoice to be in your GSTR-2B.
- Ignoring amendments — wrong invoices should be corrected through GSTR-1 amendment tables, not just “adjusted” in 3B.
- Filing 3B late “just this once” — late fees plus 18% interest, and repeated delays can flag you for departmental scrutiny.
What changed recently that you should know
- From the July 2025 tax period (monthly filers) and August 2025 (QRMP filers), the portal locks GSTR-3B after filing — corrections now flow through amendment tables rather than editing 3B.
- GSTR-1A lets you preview and confirm pending corrections before your 3B locks, closing the mismatch loop between 1 and 3B.
- Late-fee caps for GSTR-1 and GSTR-3B were standardised by Notification 09/2023-CT from 1 July 2023 — the caps in the table above are current.
Because correction windows keep evolving, make it a habit to reconcile GSTR-1 against your sales register before the 11th, and reconcile GSTR-3B against GSTR-2B before paying tax.
Frequently Asked Questions
Can I revise a filed GSTR-3B?
No — GSTR-3B cannot be revised. Since the portal began locking 3B after filing (2025), corrections are made through amendment mechanisms and reflect in later returns. File carefully the first time.
What happens if I file GSTR-1 but not GSTR-3B?
You accrue late fees on 3B and, more seriously, 18% interest on unpaid tax. Continued non-filing of 3B can block your ability to generate e-way bills and may lead to registration cancellation for persistent default.
Do nil turnover businesses still need to file?
Yes — file nil GSTR-1 and nil GSTR-3B. Nil late fee is only ₹20/day (capped), but skipping filing entirely hurts compliance rating and blocks buyers’ credit.
Is GSTR-1 required even if I am under composition scheme?
No. Composition taxpayers file CMP-08 (quarterly) and GSTR-4 (annual) instead. They issue a bill of supply, not a tax invoice, and cannot charge GST on bills.
Sources & Official References
ITR, GST returns, notices and registrations — fixed fees, human support, on-time filing.
Fact-checked on 2025-09-25 • Content library version 2025.09.1
Disclaimer: This article is for general awareness only and is not legal, tax or professional advice. Tax rules change — always confirm current rates, limits and due dates with the official government portals listed above, or consult a qualified chartered accountant or tax practitioner before acting.
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