How to file GST return online — complete 2026 guide

ITC mismatch is the single biggest GST headache for small businesses today. CBIC's own dashboard (March 2026) reports about ₹3.7 lakh crore of credit “blocked” awaiting vendor compliance across all GSTINs. The RTI route doesn't fix the vendor — but it gives you a written confirmation of your own compliance, which becomes the lever to push the vendor.

A GST return is a periodic declaration by a registered taxpayer of outward supplies (sales), inward supplies (purchases), tax collected, tax paid, and Input Tax Credit (ITC) claimed.

You must be GST-registered (and hence file returns) if any of these is true:

• Aggregate turnover exceeded ₹40 lakh in goods (₹20 lakh in special-category states) or ₹20 lakh in services in the financial year.
• You make inter-state taxable supplies (any turnover).
• You sell on e-commerce platforms (Amazon, Flipkart, Zomato, etc.) — mandatory under §24.
• You are liable to pay tax under reverse charge (§9(3) / §9(4)).
• You are an input service distributor, casual taxable person, or non-resident taxable person.

The legal anchor is the Central Goods and Services Tax Act, 2017 (CGST Act). The four most-cited sections for return filing are:

• §37 — outward supplies → GSTR-1
• §39 — periodic return + tax payment → GSTR-3B
• §44 — annual return → GSTR-9
• §47 — late fee (₹100/day CGST + ₹100/day SGST = ₹200/day, max ₹10,000 per return; reduced for nil returns)
• §50 — interest @18% per annum on tax paid late
• §16 — ITC eligibility (read with Rule 36(4) — credit only if vendor invoice in GSTR-2B)

• Open https://www.gst.gov.in
• Click “Login” → enter GSTIN (15-digit) + password + captcha.
• First-time users register at “New Registration” with PAN, mobile, email — TRN (Temporary Reference Number) generated, then GSTIN issued in 7 working days post officer approval.

GSTR-1 lists every sales invoice you raised in the period.

• “Returns Dashboard” → choose tax period → “GSTR-1 / IFF” → “Prepare Online” (or upload JSON from offline tool — Tally, ClearTax, Zoho, BUSY).
• B2B invoices (Table 4): GSTIN of buyer, invoice number, date, taxable value, IGST/CGST/SGST/cess.
• B2C Large (Table 5): inter-state B2C invoices > ₹2.5 lakh, with state code + tax break-up.
• B2C Others (Table 7): consolidated by state + rate. No invoice-level detail needed.
• Exports (Table 6A): with shipping bill / port code; choose “with payment of IGST” or “without (LUT)”.
• Credit / Debit notes (Tables 9A, 9B).
• HSN summary (Table 12): mandatory — 6-digit HSN if turnover > ₹5 cr, else 4-digit.
• Documents issued (Table 13): ranges of invoices, credit notes, vouchers issued during period.
• Click “Submit” then “File” with EVC (OTP on registered mobile + email) or DSC (companies/LLPs).

Due date: 11th of following month (monthly filer) or 13th of month following quarter (QRMP filer).

GSTR-2B is generated automatically on the 14th of each month, listing all ITC available based on suppliers' GSTR-1 filings up to the 13th. Read it carefully.

• “Returns Dashboard” → “GSTR-2B” → download Excel.
• Match every supplier invoice against your purchase register.
• If a supplier invoice is missing, ITC is NOT available that month (Rule 36(4) + §16(2)(aa)). Chase the supplier — or write to CGST Range as Mahesh did.

GSTR-3B is the actual liability return — what you collected, what ITC you're using, what cash you need to pay.

• “Returns Dashboard” → tax period → “GSTR-3B” → most fields auto-populate from GSTR-1 and GSTR-2B.
• Table 3.1 — Outward supplies: taxable, zero-rated, nil/exempt, non-GST.
• Table 4 — Eligible ITC: auto-pulled from GSTR-2B; you can reduce (for ineligible items under §17(5) — motor vehicles, food, etc.) but cannot increase.
• Table 5 — Exempt / Nil / Non-GST inward.
• Table 6.1 — Payment of tax: system computes net liability after ITC. Pay any cash shortfall via Challan PMT-06 (NetBanking / NEFT-RTGS / over-the-counter for amounts < ₹10,000).
• Submit + File with EVC / DSC.

Due date: 20th of following month (monthly filer) or 22nd / 24th of month following quarter (QRMP filer — depends on state).

If you're on QRMP, you still need to pay tax monthly even if you file return quarterly. Two methods:

• Fixed sum method: pay 35% of last quarter's cash component for months 1 and 2 of the quarter.
• Self-assessment method: compute actual liability, pay actual amount.

Pay by 25th of months 1 and 2 via PMT-06. Quarter-end tax is paid with GSTR-3B.

• Threshold: mandatory if aggregate turnover > ₹2 crore in FY. Optional for ₹2 crore and below.
• Due date: 31 December of following FY (e.g., FY 2024-25 → 31 Dec 2025; can be extended by CBIC).
• Consolidates all your monthly/quarterly data + reconciliation. If turnover > ₹5 crore, also file GSTR-9C (audited reconciliation by self).

• Threshold (since 1 Aug 2023): aggregate turnover > ₹5 crore in any preceding FY from 2017-18 onwards.
• Generate IRN (Invoice Reference Number) on https://einvoice1.gst.gov.in before issuing invoice to buyer; auto-populates QR code + IRN.
• Without IRN, the invoice is not valid for ITC purposes for your buyer — and you'll face a notice.

• Mandatory for goods movement of value > ₹50,000 (some states have lower thresholds).
• Generate at https://ewaybillgst.gov.in linked to invoice → 14-digit EBN.
• Validity: 1 day per 200 km (standard), 1 day per 20 km (over-dimensional cargo).

+----------------------+------------------------+----------------------------+
| Return + Status      | Late fee (per day)     | Cap                        |
+----------------------+------------------------+----------------------------+
| GSTR-1 (with sales)  | ₹50 (₹25 CGST + ₹25    | ₹5,000                     |
|                      | SGST)                  |                            |
+----------------------+------------------------+----------------------------+
| GSTR-1 (nil)         | ₹20 (₹10 + ₹10)        | ₹500                       |
+----------------------+------------------------+----------------------------+
| GSTR-3B (with tax)   | ₹50 (₹25 + ₹25)        | ₹5,000 (₹2,000 if t/o ≤    |
|                      |                        | ₹1.5 cr; ₹5,000 if ≤ ₹5cr) |
+----------------------+------------------------+----------------------------+
| GSTR-3B (nil)        | ₹20 (₹10 + ₹10)        | ₹500                       |
+----------------------+------------------------+----------------------------+
| GSTR-9 / 9C          | ₹200 (₹100 + ₹100)     | 0.04% of turnover (slabbed |
|                      |                        | by t/o brackets)           |
+----------------------+------------------------+----------------------------+
| Interest on tax      | 18% p.a. (§50)         | No cap                     |
+----------------------+------------------------+----------------------------+
| Interest on excess   | 24% p.a.               | No cap                     |
| ITC claim            |                        |                            |
+----------------------+------------------------+----------------------------+
| RTI to jurisdictional| ₹10 by IPO             | BPL = free                 |
| CGST PIO             |                        |                            |
+----------------------+------------------------+----------------------------+

• ITC mismatch with GSTR-2B — the most common stuck scenario. Vendor hasn't filed GSTR-1, so credit is locked. (See Mahesh's story.)
• Late fee accumulating — even nil returns charge ₹20/day if not filed on time. Many small taxpayers stop filing for 6 months and find ₹3,000+ has piled up.
• E-invoice not generated for B2B above the threshold — buyer's ITC denied; auto-cascading penalty.
• HSN code wrong — return submits but raises a flag in scrutiny; mismatched HSN can also block ITC for the buyer.
• Reverse charge missed under §9(3) (specified categories like GTA, legal services, security services) or §9(4) (purchase from unregistered person — limited applicability post 2019). Detected only at audit; back-tax + interest + penalty.
• Export under LUT not flagged — return shows IGST liability instead of zero-rated; refund route changes entirely.
• Cancelled invoices not declared in credit notes — sales over-reported, GST overpaid, refund needed.
• QRMP PMT-06 monthly payment missed — interest @18% from due date even though you'll pay at quarter end.
• GSTIN suspended — usually for not filing returns for 2-3 consecutive periods; you'll see “your GSTIN has been suspended” on login. Revocation requires REG-21 within 90 days.

• GST Self-Service helpdesk: 1800-103-4786 (toll-free, Hindi/English, 9 am – 9 pm).
• CBIC Mitra Helpdesk: cbicmitra.helpdesk@icegate.gov.in / 1800-1200-232.
• Best for: portal errors, password reset, EVC not received, challan reconciliation.

• “Services” → “User Services” → “Grievance / Complaints”.
• Choose grievance type (return-related, refund-related, registration-related).
• Reference number generated; SLA 7-15 days. No statutory force.

• https://pgportal.gov.in → “Department of Revenue” → “GST Council / CBIC”.
• Routes to a Joint Commissioner. Useful for delayed refunds and unanswered scrutiny notices.

• Find your jurisdictional CGST Range / Division: gst.gov.in → “Search Taxpayer” → enter your GSTIN → see Range Code + Division Code.
• Write to the Deputy / Assistant Commissioner of your Range with copies of unanswered tickets.
• For appeal against orders → file APL-01 (first appeal to Joint / Additional Commissioner-Appeals) within 3 months of order, with 10% pre-deposit of disputed tax.

The CBIC, every Central GST Commissionerate, every State GST/Commercial Tax Department, and the GSTN itself are public authorities under §2(h) of the RTI Act 2005.

RTI helps here when:

• Refund (export refund / inverted-duty refund) is “approved” but not credited — RTI to PIO at jurisdictional CGST Division asks for the FORM RFD-05 sanction order date and the bank-side push status.
• ITC has been blocked under Rule 86A but no show-cause notice was issued — RTI for the basis of blocking + the officer's recorded reasons.
• Scrutiny notice received under §61 with vague reasons — RTI for the underlying risk parameter / ASMT-10 supporting documents.
• Vendor compliance dispute as in Mahesh's case — RTI confirms your own GSTIN is in good standing, giving you written ammunition to push the vendor + their jurisdictional Range office.

See the dedicated guide: RTI for GST refund stuck — copy-ready template.

RTI does NOT help here when:

• Routine return filing with vendor mismatch — fix the vendor compliance first; RTI cannot create ITC where the law denies it.
• Late fee dispute on a confirmed delayed return — late fee is automatic by §47; only a CBIC waiver notification (which is publicly available) can reduce it.
• Disagreement with an adjudication order — file appeal under §107 within 3 months; RTI is not an appeal substitute.
• Tariff classification opinion — file an Advance Ruling application before the Authority for Advance Rulings (AAR) with prescribed fee.

Q. I'm under the composition scheme. Do I file GSTR-1 / 3B?
No. Composition dealers (turnover ≤ ₹1.5 cr in goods, ≤ ₹50 lakh in services) file CMP-08 quarterly (paying 1% / 5% / 6% turnover-based tax) and GSTR-4 annually by 30 June. No regular GSTR-1 / 3B; no ITC available.

Q. Can I revise GSTR-1 or GSTR-3B?
GSTR-1 cannot be revised once filed — but errors can be corrected in the next period's GSTR-1 amendment tables. GSTR-3B also cannot be revised; corrections (additional liability or excess credit reversal) flow through next month's 3B with applicable interest.

Q. My GSTIN was suspended for non-filing. How do I revive it?
File all pending returns (with late fee + interest), then apply for Revocation of Cancellation in REG-21 within 90 days of the cancellation order. Officer has 30 days to decide. If outside 90 days, file an appeal under §107 with condonation request.

Q. I'm an exporter — must I pay IGST or use LUT?
LUT (Letter of Undertaking) lets you export zero-rated without paying IGST upfront — file LUT in RFD-11 at the start of each FY, no fee, valid one year. Otherwise pay IGST and claim refund — slower (60-90 days typical).

Q. The portal says “Tax payment failed” but money is debited from my bank.
This is a CIN-not-generated issue. Wait 24 hours — usually auto-reconciles. If not, raise grievance on portal with bank reference + CIN attempt time. If still stuck after 7 days, RTI to PIO of CGST/GSTN.

Q. ITC was reversed in my GSTR-2B — what happened?
Vendor filed an amendment / credit note / cancelled invoice in their GSTR-1. Ask them — if it's a genuine cancellation, the reversal is correct. If it's a mistake, they should re-issue and re-file in next period.

Q. I missed the QRMP opt-out window. Stuck quarterly for the year?
Yes — once selected, QRMP applies for the full year; opt-out is only allowed at start of FY (window: 1 Feb – 30 April for next FY). Plan ahead.

Q. My buyer is asking why their GSTR-2B doesn't show my invoice.
Check that you filed GSTR-1 with their correct GSTIN, the correct tax period, and that the invoice was in Table 4 (B2B). One wrong digit in GSTIN means the credit goes to a different (or invalid) GSTIN. Amend in next GSTR-1.

• RTI for GST refund stuck — copy-ready template
• RTI in 12 simple steps — for first-time filers
• All Indian government helplines — one master directory
• RTI forms + state-wise fee chart
• All "money & schemes" RTI guides

Last reviewed: 26 April 2026 by RTI Wiki editorial team. GST law evolves through Council meetings — verify current thresholds, late fee waivers, and notifications on cbic-gst.gov.in or write to admin@bighelpers.in.