Log into services.gst.gov.in. Open Returns Dashboard. First, file GSTR-1 by the 11th: enter B2B sales invoices, B2C totals, and mandatory HSN summaries; verify with OTP. Next, download auto-drafted GSTR-2B on the 14th to confirm eligible supplier input tax credit (ITC). Finally, file GSTR-3B by the 20th: sales and eligible ITC auto-populate. If net tax remains, generate a PMT-06 challan, pay instantly via NetBanking or UPI, click Offset Liability, and submit with Aadhaar OTP. For zero business, submit an instant Nil Return online or via SMS to 14409. Your GST is filed!
1. The GST Return Lifecycle: Understanding GSTR-1, 2B & 3B
The Goods and Services Tax (GST) compliance engine operates on a synchronized monthly or quarterly two-part return framework. Rather than reporting all your financial data in one single form, the GST law separates what you sold from what you owe:
| Return Form | Core Purpose | Filing Due Date | Key Requirement |
|---|---|---|---|
| GSTR-1 | Statement of Outward Supplies (All B2B and B2C sales, exports, credit notes) | 11th of every month (Monthly filers) or 13th (QRMP quarterly filers) | Must be filed FIRST. Once filed, your buyers receive their Input Tax Credit. |
| GSTR-2B | Static auto-generated Input Tax Credit (ITC) statement drafted by the portal | Generated automatically on the 14th of every month | View-only reconciliation statement. You can only claim ITC that appears here (Section 16(2)(aa)). |
| GSTR-3B | Self-declared summary return for tax payment, ITC claims, and offset | 20th of every month (or 22nd/24th under QRMP scheme) | Calculates net tax payable after offsetting eligible ITC from GSTR-2B against outward tax liability. |
Under Rule 59(6) of the CGST Rules, you cannot file GSTR-3B without first filing GSTR-1 for that month. Furthermore, if you fail to file GSTR-3B for a preceding tax period, the portal automatically blocks you from filing GSTR-1 for future periods. Always follow the sequence: GSTR-1 → GSTR-2B review → GSTR-3B & Payment.
2. Essential Pre-Filing Checklist: What to Assemble
Before logging into the portal, assemble your primary transaction registers for the month:
- Sales Invoice Register: All tax invoices issued to registered buyers (B2B) with their 15-digit GSTIN, invoice numbers, dates, taxable values, and applicable tax rates (5%, 12%, 18%, 28%).
- B2C Retail Summary: Total value of sales made to unregistered consumers, consolidated by POS (Place of Supply state code) and GST tax slab.
- Credit / Debit Notes: Any credit notes issued for returned goods or billing adjustments during the month.
- HSN Summary: Harmonized System of Nomenclature (HSN) codes for all products or SAC codes for all services provided, along with total quantity and taxable turnover.
- Purchase Invoices: Vendor bills from your suppliers with proof of bank payment to reconcile against GSTR-2B.
- Active Mobile / Email: Required to receive the 6-digit Electronic Verification Code (EVC) for instant return signing without a digital token.
3. Step-by-Step: How to Prepare and File GSTR-1 (Outward Supplies)
GSTR-1 captures your outward sales. Follow these sequential steps on the GST portal:
Portal Access & Dashboard Navigation
Open https://services.gst.gov.in. Click Login and enter your 15-digit Username, Password, and CAPTCHA. On your user dashboard, click Return Dashboard (or navigate via Services > Returns > Returns Dashboard). Select the Financial Year (e.g. 2025-26 or 2026-27) and the Return Filing Period (Month). Click Search.
Enter Invoices in GSTR-1 Tables
Under the tile "Details of outward supplies of goods or services (GSTR-1)", click Prepare Online.
You will see standard reporting tables:
• Table 4A - B2B Invoices: Click Add Record. Enter the buyer's GSTIN (the legal name auto-populates). Enter Invoice Number, Invoice Date, Total Invoice Value, and select the Supply Type (Inter-State or Intra-State). Enter taxable values under respective tax slabs (IGST for out-of-state, or CGST + SGST for within-state). Click Save.
• Table 5A - B2C (Large) Invoices: Enter inter-state invoices to unregistered consumers where the invoice value exceeds ₹2,50,000.
• Table 7 - B2C (Others): Enter consolidated monthly retail sales to consumers. Select POS state, taxable value, and GST rate.
• Table 9B - Credit / Debit Notes: Enter any notes issued to registered buyers.
Fill Mandatory HSN Summary (Table 12) & Document Summary (Table 13)
• Table 12 (HSN-wise Summary): Enter the 4-digit or 6-digit HSN/SAC code, description, Unit Quantity Code (UQC), total quantity, total taxable value, and tax amounts. The total taxable value in Table 12 must strictly match the sum of Tables 4, 5, and 7!
• Table 13 (Documents Issued): Enter the starting and ending serial numbers of tax invoices issued during the month, cancelled invoices, and net issued count.
Generate Summary & File GSTR-1 with EVC
Click Generate Summary at the bottom of the page. Wait 60 seconds and refresh the page. Click Proceed to File / Summary. Review the draft PDF report to verify that total sales and tax liabilities match your billing software. Check the declaration checkbox, select the Authorized Signatory from the dropdown, and click File with EVC. Enter the 6-digit OTP sent to your registered mobile and email. Click Verify. Your GSTR-1 status updates to "Filed" with an instant Application Reference Number (ARN).
4. Step-by-Step: GSTR-2B Input Tax Credit (ITC) Reconciliation
Under Section 16(2)(aa) of the CGST Act, you cannot claim Input Tax Credit on purchases unless your vendor has actually filed their GSTR-1 and the invoice appears in your GSTR-2B statement.
If your GSTR-3B ITC exceeds your GSTR-2B credit by more than a predefined threshold, the GST portal automatically generates a computerized scrutiny notice in Form DRC-01C. You will have only 7 days to pay back the excess credit with 18% interest or provide a detailed justification, failing which your subsequent GSTR-1 filings will be frozen!
How to Check GSTR-2B on the 14th
1. Go to Returns Dashboard and select the month.
2. Click View under "Auto-drafted ITC Statement for the month (GSTR-2B)".
3. Review Part A - ITC Available: Check B2B invoices uploaded by suppliers. Note down the total available IGST, CGST, and SGST.
4. Review Part B - ITC Not Available: Inspect invoices where credit is blocked (e.g., supplier filed after cutoff, or recipient location restrictions).
5. Step-by-Step: Filing GSTR-3B & Offsetting Tax Liability
GSTR-3B is where taxes are calculated, credits offset, and final liabilities paid. Follow this procedure between the 15th and 20th:
Open GSTR-3B in Returns Dashboard
Select the return period on the dashboard and click Prepare Online under Monthly Return GSTR-3B. If you have zero transactions, check "Do you want to file Nil return?" to skip directly to verification. Otherwise, click Next.
Verify Auto-populated Sales & Eligible ITC
The GST portal automatically pre-populates figures:
• Table 3.1 (Outward Supplies): Verify that taxable values and tax liabilities match your filed GSTR-1.
• Table 4 (Eligible ITC): Confirm that ITC auto-populated from GSTR-2B matches your purchase records. If you purchased ineligible goods (e.g. food, club memberships, motor vehicles u/s 17(5)), enter the blocked amounts under Table 4(B) ITC Reversed.
Click Save GSTR-3B.
Compute Liabilities & Offset Taxes
Click Compute Liabilities at the bottom. The system executes the statutory tax offset order:
1. IGST credit is exhausted first against IGST liability, then CGST, then SGST.
2. CGST credit is offset against CGST and balance IGST.
3. SGST credit is offset against SGST and balance IGST (CGST and SGST can never be cross-utilized).
After credit utilization, inspect the Cash Required column. If cash balance is zero, your credits covered everything!
Generate PMT-06 Challan (If Cash is Due) & Submit Return
If a cash balance is required, click Create Challan. The portal auto-fills Form GST PMT-06 with the exact tax, interest, and late fee amounts. Select Payment Mode: E-Payment (NetBanking / UPI). Complete the bank authorization. Your Electronic Cash Ledger updates within seconds. Return to GSTR-3B, click Make Payment / Post Credit to Ledger, and click Proceed to File. Select Authorized Signatory, click File GSTR-3B with EVC, enter the OTP, and receive your confirmation ARN!
6. Filing Nil GST Returns in 60 Seconds: Portal & SMS
If you made zero purchases, zero sales, have no reverse-charge liabilities, and hold no pending late fees for the month, you can file your Nil return in two lightning-fast ways:
Online Portal Nil Filing (1 Click)
Open GSTR-1 or GSTR-3B on the Returns Dashboard. Select "File Nil GSTR-1" or check "Do you want to file Nil return?" in GSTR-3B. Click File Return, choose Authorized Signatory, enter the mobile OTP, and your Nil return is instantly completed.
Instant SMS Nil Filing (No Internet Required)
From your registered mobile number, send an SMS to 14409 in this format:
NIL 3B 07AAAAA0000A1Z5 052026 (Replace with your 15-digit GSTIN and Month/Year MMYYYY).
You will receive a 6-digit verification code via SMS valid for 30 minutes. Confirm by replying:
CNF 3B <Verification Code> to 14409.
You will receive an immediate SMS containing your official filing ARN!
7. 5 Critical Traps: Automated Notices, Blocked ITC & Penalties
Avoid these critical compliance oversights that trigger automated tax demands:
- Trap 1: GSTR-1 vs GSTR-3B Mismatch (Rule 88C): If outward tax declared in GSTR-1 is greater than GSTR-3B, the system issues an automated DRC-01B notice demanding payment of the difference with interest within 7 days.
- Trap 2: Claiming Blocked Credit under Section 17(5): Goods and services used for personal consumption, food/catering, club memberships, health insurance (unless legally mandated for employees), and motor vehicles are ineligible for ITC, even if they appear in GSTR-2B.
- Trap 3: Not Reversing ITC on Invoices Unpaid for 180 Days: Under the second proviso to Section 16(2), if you fail to pay your vendor within 180 days from the invoice date, you must mandatorily reverse the claimed ITC along with 18% interest!
- Trap 4: Missing the Due Date (Late Fee u/s 47): A daily late fee of ₹50/day (₹20/day for Nil returns) applies automatically. More critically, interest at 18% per annum accrues under Section 50 on net cash payable.
- Trap 5: E-Way Bill Generation for Consignments > ₹50,000: If moving goods worth more than ₹50,000 inter-state (or state-specific intra-state limits), you must generate an E-Way Bill on ewaybillgst.gov.in prior to transit.
8. Frequently Asked Questions (FAQ)
Can I edit or revise a GST return after filing?
Unlike Income Tax Returns, GST returns cannot be revised once filed. Any corrections to invoice details, values, or tax rates must be amended in the subsequent month's GSTR-1 under Table 9A (Amended B2B) or Table 10 (Amended B2C), and tax differences adjusted in the next GSTR-3B.
What is the QRMP scheme, and should small businesses opt for it?
The Quarterly Return Monthly Payment (QRMP) scheme allows registered taxpayers with turnover up to ₹5 Crores to file GSTR-1 and GSTR-3B once every quarter instead of every month. However, taxes must still be deposited monthly using the Invoice Furnishing Facility (IFF) and Form PMT-06 challans.
How does Input Tax Credit cross-utilization work?
IGST credit can be used to pay IGST, CGST, and SGST in any proportion. CGST credit can pay CGST and IGST. SGST credit can pay SGST and IGST. CGST credit cannot be used to pay SGST, and SGST credit cannot pay CGST. The portal's offset engine calculates this automatically.