How to File Your GST Return Form: GSTR-1, GSTR-3B, and Nil SMS

To file a GST return, log in to the GST portal at gst.gov.in, open the Returns Dashboard for your tax period, prepare GSTR-1 with your sales invoice details and GSTR-3B with your tax summary and input tax credit, pay any balance through a challan, and authenticate the submission with a Digital Signature Certificate or Electronic Verification Code. The portal generates an Acknowledgement Reference Number on success, and that number is your proof of filing.

Which Return You File and When

Your registration type and turnover decide which forms you owe. Regular taxpayers file two recurring returns: GSTR-1 for outward supplies (sales) and GSTR-3B for the tax summary and payment.¹²

Monthly filers submit GSTR-1 by the 10th of the following month and GSTR-3B by the 20th. If your aggregate annual turnover in the preceding financial year was ₹5 crore or less, you can opt into the Quarterly Returns with Monthly Payment (QRMP) scheme, which lets you file both returns quarterly while still paying tax each month via challan.³⁴ Under QRMP, GSTR-3B is due on the 22nd or 24th of the month after the quarter ends, depending on the state of your principal place of business. Turnover above ₹5 crore locks you into monthly filing.⁵

Two boundaries worth stating up front. Composition-scheme taxpayers do not file GSTR-1 or GSTR-3B; they file a single annual return in GSTR-4.⁶ And if your registration has been cancelled, you owe GSTR-10 within three months of the cancellation date or order, whichever is later, reporting the stock held on the day before cancellation.⁷ Regular taxpayers also owe an annual consolidation in GSTR-9 by December 31 of the following financial year.⁸

You must file GSTR-1 even for a period with no activity. A nil return still has to be submitted.⁹

What to Gather Before You Log In

Have the following ready:

Your 15-digit GSTIN.
For every sale in the period: invoice number, date, recipient’s GSTIN for B2B, taxable value, and applicable tax rate. B2C sales are grouped by tax rate or state of consumption.¹
HSN codes for goods and SAC codes for services.
Credit and debit notes, with the original invoice reference for each.
Self-invoices and payment vouchers for any supplies received under reverse charge, such as legal services from advocates, goods transport agency services, or director services to a company.¹⁰
Shipping bills and other export documentation if you exported goods or services.

If your aggregate annual turnover exceeded ₹5 crore in any financial year from 2017–18 onward, you must generate e-invoices through the Invoice Registration Portal for B2B, business-to-government, and export supplies.¹¹ Each e-invoice gets an Invoice Reference Number, and the data auto-populates several GSTR-1 tables: B2B invoices (Tables 4A, 4B, 4C), export invoices (Table 6A), and credit/debit notes.¹² Review the auto-populated figures before submission; the system fills them in but does not verify them.

Filing GSTR-1

Log in at gst.gov.in and go to Services → Returns → Returns Dashboard. Select the financial year and tax period, then click Prepare Online on the GSTR-1 tile. Offline preparation through the Returns Offline Tool or a GST Suvidha Provider is also available.¹²

Fill in the tables by transaction type. B2B sales need invoice-level entry: recipient’s GSTIN, invoice number and date, taxable value, and the breakdown of Central Tax, State/UT Tax, Integrated Tax, and cess.¹ Interstate B2C sales above ₹2.5 lakh also need invoice-level detail. Below that threshold, and for all intrastate B2C sales, report a consolidated summary grouped by tax rate.⁹

A few portal rules to keep in mind. Duplicate invoice numbers are rejected. All values must go in to two decimal places. You can edit or delete entries as often as you need until final submission. When the data is complete, click Generate GSTR1 Summary, review the totals, and proceed to submit. The summary can only be regenerated at ten-minute intervals.¹²

Filing GSTR-3B

Back on the Returns Dashboard for the same period, click Prepare Online on the GSTR-3B tile. A short questionnaire narrows the return to the tables that apply to you.² The main tables you complete:

Table 3.1, outward and reverse charge supplies, is auto-drafted from your GSTR-1 and GSTR-2B. Confirm or edit the taxable value and tax split for outward supplies, inward supplies under reverse charge, and supplies through e-commerce operators.
Table 4, eligible ITC. Row 4A is available ITC including imports and reverse charge, Row 4B is ITC reversals, and Row 4C is the net ITC.
Table 5 captures exempt and nil-rated inward supplies and non-GST purchases.
Table 5.1 auto-calculates interest and late fee. The interest figure is editable.
Table 6.1 is the payment step. Click Proceed to Payment, and the system fills in what can be set off through ITC. Any remaining balance is paid from the electronic cash ledger.

GSTR-3B is largely self-declared; the system does not auto-fill everything.¹³ Check every figure against your books before you file, because the return becomes permanent once submitted.

Reconcile Your Input Tax Credit First

ITC is one of the most common places filings go wrong. Section 16(2) of the CGST Act sets four conditions: you must hold a valid tax invoice, you must have received the goods or services, the supplier must have paid the tax to the government, and you must have filed your own return.¹⁴ In practice, the invoice also has to appear in your GSTR-2B, the static monthly ITC statement generated on the 14th of each month (12th for quarterly filers).

Reconcile against GSTR-2B, not GSTR-2A. GSTR-2B freezes once generated and separates eligible from ineligible credits; GSTR-2A is dynamic and keeps changing as suppliers upload invoices.¹⁵ If a supplier’s invoice is missing from your GSTR-2B, follow up with the supplier before claiming that credit.

One more check before you file: the 180-day rule. If you have not paid a supplier the full invoice value plus tax within 180 days of the invoice date, you must reverse the ITC claimed on that purchase and pay interest on the reversed amount. You can reclaim the credit once payment is made.¹⁴ If you have aging payables, run through them against the 180-day window before each GSTR-3B.

Paying Tax and Creating a Challan

If GSTR-3B shows a net liability after ITC, the portal will not let you file until the balance is paid. Click Create Challan, which generates Form GST PMT-06.¹⁶ Payment modes available:

Net banking through your bank’s online portal.
Credit or debit card, completed online after selecting your bank.
BHIM UPI via a linked bank account.
NEFT/RTGS: download the challan, add the beneficiary in your bank account, and transfer the funds. The portal updates after confirmation from RBI.
Over the counter: print the challan and deposit cash, cheque, or demand draft at the chosen branch.

QRMP quarterly filers see an auto-populated monthly challan set at 35% of the tax paid from the electronic cash ledger in the previous quarter’s GSTR-3B, and pay this each month even though the return itself is quarterly.¹⁶

Authenticate and Save the ARN

Once the return is complete and any tax is paid, click Proceed to File. Tick the declaration, select your authorized signatory, and authenticate with one of two methods:¹⁷

Digital Signature Certificate (DSC), issued by an authorized certifying authority. Mandatory for all companies and LLPs.
Electronic Verification Code (EVC), a one-time password sent to the authorized signatory’s registered mobile number. Available for proprietorships, partnerships, and other non-corporate entities.

The status changes to “Filed” and the portal issues an Acknowledgement Reference Number, with an SMS and email confirmation to the primary authorized signatory.¹² Save the ARN. It is your proof of filing and the key you use to track return status under Services → Returns → Track Return Status. Download the signed PDF copy of the filed return and keep both digital and physical copies. Records must be retained for at least 72 months from the due date of the annual return for the year they cover.¹⁸

Filing a Nil GSTR-3B by SMS

If you had zero inward and outward transactions and no ITC to claim, you can file a nil GSTR-3B without logging in. From your registered mobile number, send an SMS to 14409 in this format:

NIL 3B [15-digit GSTIN] [tax period as MMYYYY]

Example: NIL 3B 09XXXXXXXXXXXZC 062026

You will receive a six-digit verification code valid for 30 minutes. Reply with CNF 3B [6-digit code]. An acknowledgement number is sent on successful filing. Text SMS HELP 3B to 14409 if you need format help.

What Late Filing Costs

The statutory late fee under Section 47 of the CGST Act is ₹100 per day (₹50 CGST plus ₹50 SGST) per return, capped at ₹5,000 per act.¹⁹ Notifications have reduced these figures in practice: for GSTR-1 and GSTR-3B with any tax liability, the effective fee is ₹50 per day (₹25 + ₹25); nil returns attract ₹20 per day (₹10 + ₹10). Maximum caps depend on turnover:²

Nil returns: ₹500 (₹250 CGST + ₹250 SGST).
Turnover up to ₹1.5 crore: ₹2,000.
Turnover between ₹1.5 crore and ₹5 crore: ₹5,000.
Turnover above ₹5 crore: ₹10,000.

Interest under Section 50(1) runs at up to 18% per year on unpaid tax, calculated from the day after the due date until payment.²⁰ Wrongly claimed and used ITC attracts 24% per year. Interest is generally charged on the net cash tax liability (gross liability minus legitimate ITC), unless the department finds intent to evade, in which case it applies to the gross liability.

Persistent non-filing has a heavier consequence. Regular taxpayers who fail to file returns for six consecutive months risk having their GST registration cancelled by the authorities, after which they can no longer issue tax invoices or collect GST.²¹ If cancellation happens, GSTR-10 is due within three months.⁷

1
Goods and Services Tax Council. Statement of Outward Supplies (GSTR-1) in GST
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GST Portal. How Can I Create, Save, Pay Taxes and File Form GSTR-3B Return?
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DCMSME. Circular No. 143/13/2020 – GST
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GST Portal. FAQs – Form to Change Profile for QRMP Scheme
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GST Portal. Form to Change Profile for QRMP Scheme
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Goods and Services Tax. FAQs – Filing Form GSTR-4 (Annual Return)
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GST Portal. Create Challan (Post Login)
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18
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21
GST Council. Cancellation of Registration in GST