GST Return Filing (GSTR-1/3B/9)

Who can use this

• All registered GST taxpayers
• Regular taxpayers with monthly filing obligations
• Businesses not under Composition Scheme
• Importers and exporters
• E-commerce operators

Who cannot use this

• Businesses under Composition Scheme
• Unregistered businesses
• Taxpayers with nil supply or exempted supplies only

Documents required

• GSTR-1 filing proof (sales invoice details)
• Purchase invoices and GSTR-2B auto-populated data
• Tax paid certificates (ITC certificates)
• Bank statements showing GST payments
• Import and export shipping documents (if applicable)
• TDS/TCS certificates

Step-by-step process

1. Log in to GST portal with your GSTIN credentials — Visit https://www.gst.gov.in. Click 'Login'. Enter your username (email or GSTIN), password, and verify OTP. Ensure you have the correct GSTIN account.
2. Navigate to GSTR-3B filing section — From the dashboard, click 'Services' > 'Returns' > 'GSTR-3B'. You will see a list of months for which you can file.
3. Select the month and year for filing — Click on the month and year for which you want to file GSTR-3B. For example, 'April 2025' for the April 2025 GST period. Ensure you are filing within the due date.
4. Review your auto-populated GSTR-2B (purchase data) — The system will display GSTR-2B, which auto-populates supplier invoices. Review the data for accuracy. Verify that all your suppliers' invoices are correctly listed.
5. Enter outward supplies (sales) details — In Section 3, enter your total outward supplies from GSTR-1: taxable supplies, exempt supplies, zero-rated supplies (exports), and supplies to consumers. Verify amounts match your GSTR-1 filing.
6. Declare ITC (Input Tax Credit) eligibility — In Section 4, declare your Input Tax Credit eligibility. You can claim ITC on purchases used for making taxable supplies. The portal will show available ITC from GSTR-2B.
7. Review ineligible ITC details — If any portion of your purchased goods/services is not used for taxable supplies, declare ineligible ITC. Enter details of supplies for which you cannot claim ITC (e.g., personal consumption, exempted supplies).
8. Enter tax liability calculation — In Section 5, the portal will auto-calculate your tax liability: CGST, SGST/UTGST, IGST on your outward supplies. Verify the calculation is correct based on your sales value and applicable tax rates.
9. Declare taxes already paid (advance/installments) — In Section 6, enter any GST taxes you have already paid during the month: advance tax, installment payments, or TDS/TCS received. Enter amount and date of payment.
10. Add deferred tax liability (if applicable) — If you have any deferred tax liability (e.g., payment liability on reverse charge transactions), enter those details in this section.
11. Review net GST payable or refund due — The system will calculate: Net GST = Tax Liability - ITC - Advance Tax Paid. If positive, you owe GST. If negative, you have a refund credit to carry forward.
12. Review all details in the summary page — The portal displays a comprehensive summary: outward supplies, ITC claimed, tax liability, advance paid, and net amount due. Verify each section for accuracy before submission.
13. Submit GSTR-3B return — Click 'Submit' button. You will be prompted to verify via DSC (Digital Signature) or OTP. Choose your verification method and complete it.
14. Complete verification (DSC or OTP) — If using DSC: the return will be digitally signed with your certificate. If using OTP: you will receive an OTP on registered mobile; enter it to verify and submit.
15. Download acknowledgement and note filing details — After successful submission, download your GSTR-3B acknowledgement PDF. Note the filing date and time. The system will show 'Return Filed' status.

GSTR-1 and GSTR-3B do different jobs, and they are compared

GSTR-1 reports outward supplies invoice by invoice and populates your customers' input credit — file it wrong and you damage their credit as well as your record. GSTR-3B is the summary return where liability is computed and paid. Both draw on the same sales, so the department compares them, and an unexplained difference is one of the most routine queries raised. Reconcile the two before filing, not after.

Returns file in sequence, so one gap blocks everything after it

A pending period prevents the next return from being submitted, which turns a single lapse into a chain while late fees accrue on every outstanding period at once. Sustained non-filing opens cancellation proceedings under REG-17, and restoring a cancelled registration is far more work than filing was. A nil return takes minutes and can be filed by SMS — filing it keeps the sequence unbroken.

Claim input credit from GSTR-2B, not from your purchase register

Credit is available on the basis of what appears in your auto-populated GSTR-2B, which reflects what suppliers actually reported. An invoice in your books but absent from 2B is not yet claimable, and taking it anyway means reversing it later with interest. Reconciling 2B against purchases every month, and chasing gaps in the same month, is the single highest-value routine in GST compliance.

Interest runs on the cash portion; the late fee does not care

Interest under section 50 is charged at 18% a year on the tax actually discharged in cash for the delayed period, not on gross liability before credit. The late fee under section 47 accrues per day regardless of how the liability was settled, subject to a turnover-linked ceiling that is lower for nil returns. The two behave in opposite ways, which is why estimating one and assuming the other follows produces surprises.

QRMP is quarterly in name and monthly in cash

Under the QRMP scheme GSTR-1 and GSTR-3B move to a quarterly cycle, but payment continues every month through PMT-06. That gap is where a large share of late fees originate, because the scheme is remembered as quarterly and the monthly payment is not. Offset order also matters — IGST credit must be used first, and CGST credit cannot be set against SGST liability. The annual return consolidates all of this at year end.

More GST services

• GST Annual Return (GSTR-9/9C)
• GST Registration (GSTIN)

Related reading

• GSTR-1 Filing Guide 2026: Due Dates, QRMP and Late Fees
• Missed the ITR Deadline for AY 2026-27? Your Options
• GST Registration Cancellation and Revocation — REG-16, REG-21, the 90-Day Window and GSTR-10