How to File GSTR-1 and GSTR-3B: Step-by-Step Guide

GSTR-1 and GSTR-3B are the two returns most regular GST taxpayers file. Accountants handle them every month or quarter, so knowing the flow is a core job skill. This guide walks through how to file GSTR-1 and GSTR-3B on the GST portal.

Note: GST rules, due dates and portal screens change through notifications and GSTN advisories. Always check the latest advisory on gst.gov.in before filing.

GSTR-1 vs GSTR-3B at a glance

QRMP due dates for GSTR-3B vary by state category, so check the portal for yours.

Before you start: checklist

• GSTIN login credentials for gst.gov.in
• Sales register for the period, reconciled with books (for example, from TallyPrime)
• Credit/debit notes and amendments
• HSN-wise summary of outward supplies
• Document summary (invoice serial numbers issued and cancelled)
• DSC (for companies and LLPs) or Aadhaar/mobile EVC access

How to file GSTR-1 step by step

1. Log in to gst.gov.in and go to Services > Returns > Returns Dashboard.
2. Select the financial year, quarter and period, then click Search.
3. On the GSTR-1 tile, choose Prepare Online (or upload a JSON prepared through the offline tool or accounting software).
4. Fill the relevant tables, mainly:
5. B2B invoices (supplies to registered persons)
6. B2C (Large) invoices
7. B2C (Others) summary
8. Credit/debit notes (registered and unregistered)
9. Exports, if any
10. Advances and adjustments, if any
11. HSN-wise summary
12. Documents issued
13. Click Generate GSTR-1 Summary and review the summary and preview for errors.
14. Tick the declaration, choose the authorised signatory and file with DSC or EVC.
15. Download the filed return and acknowledgement for your records.

Mistakes in a filed GSTR-1 can be amended through GSTR-1A (before filing GSTR-3B of the same period) or in a later period’s GSTR-1, as the portal allows.

How to file GSTR-3B step by step

1. Check ITC first. Open GSTR-2B for the period and reconcile it with your purchase register. Use the Invoice Management System (IMS) to accept, reject or keep pending the invoices your suppliers uploaded, then recompute GSTR-2B if needed.
2. Go to Returns Dashboard, select the period and open GSTR-3B > Prepare Online.
3. Review auto-populated values. Outward supply details come from your GSTR-1/IFF and ITC from GSTR-2B. Verify them against your books before editing anything.
4. Table 3.1 – outward taxable supplies, zero-rated, nil-rated/exempt, inward supplies liable to reverse charge and non-GST supplies.
5. Table 3.2 – inter-state supplies to unregistered persons, composition dealers and UIN holders.
6. Table 4 – eligible ITC, reversals and ineligible ITC.
7. Table 5 and 5.1 – exempt/nil inward supplies and interest/late fee, if applicable.
8. Click Save, then Proceed to Payment. The system shows the tax payable; offset it using the electronic credit ledger (ITC) and the electronic cash ledger. Create a challan if the cash balance is short.
9. Tick the declaration and file with DSC or EVC. Download the filed return.

Watch: GST interview questions and answers

Common mistakes to avoid

• Filing GSTR-3B without reconciling GSTR-2B with the purchase register
• Claiming ITC on invoices not reflected in GSTR-2B, or on blocked credits
• Mismatch between GSTR-1 and GSTR-3B outward supply values
• Wrong place of supply (IGST vs CGST/SGST)
• Missing reverse charge liability
• Waiting till the last day and paying late fee and interest

Learn GST return filing hands-on

Reading steps is a start; filing real returns under supervision builds confidence. Skillshort’s Accounts Expert program covers GSTR-1, GSTR-3B, GSTR-2A/2B reconciliation, GSTR-1 and GSTR-3B from TallyPrime with JSON export, e-invoice, e-way bill and the annual return overview, every Sunday alongside your job. See our GST course in Kolkata. New to accounting? Start with the Tally course in Kolkata.

Classes are held at our Minto Park, Sovabazar and Rabindra Sarobar centres. Fees & EMI details ke liye counsellor se baat karein.