How to file GST returns yourself: GSTR-1 and GSTR-3B explained (2026)

If you are GST-registered, your returns are due every month (or quarter under QRMP) — even a nil return, or late fees start piling up. The good news: filing GSTR-1 and GSTR-3B yourself is straightforward once you know the routine. Here's how, step by step, for 2026.

Which returns, and how often?

Every regular GST-registered business files two core returns each tax period: GSTR-1 (your outward supplies — sales and debit/credit notes) and GSTR-3B (the summary return that declares tax liability and input tax credit). A nil return is still a return — if you had no sales, no purchases and no tax, you must file both anyway, or the late fees accumulate.

• Monthly filers: businesses with aggregate annual turnover above ₹5 crore file GSTR-1 and GSTR-3B every month.
• QRMP scheme: businesses with turnover up to ₹5 crore can file quarterly while paying tax monthly — GSTR-1 and GSTR-3B become quarterly, with the Invoice Furnishing Facility (IFF) letting you upload B2B invoices in the first two months so your buyers get credit earlier.

Composition taxpayers file a separate, lighter return (GSTR-CMP-08) quarterly.

Step 1 — File GSTR-1 (outward supplies)

1. Log in at www.gst.gov.in and open Services → Returns → Returns Dashboard
2. Select the financial year and return period, and choose GSTR-1 → Prepare Online (or upload via the offline utility)
3. Review the auto-populated details from e-invoices and the Invoice Management System, then add any missing B2B invoices, B2C summary, credit/debit notes and exports
4. Click Generate GSTR-1 Summary and check the consolidated liability
5. Submit and file with a Digital Signature Certificate or EVC/OTP — you will get an ARN reference

Step 2 — File GSTR-3B (summary return)

1. From the same Returns Dashboard, open GSTR-3B → Prepare Online and answer the questionnaire
2. Check Table 3.1 (outward supplies and reverse charge, auto-drafted from GSTR-1) and Table 4 (eligible input tax credit, auto-drafted from GSTR-2B) — cross-verify ITC against your purchase book before proceeding
3. Click Proceed to Payment — the portal offsets your ITC from the Electronic Credit Ledger, and any cash liability is paid via a challan (net banking, UPI, NEFT)
4. Submit and sign with DSC or EVC

GSTR-2B and the Invoice Management System

GSTR-2B is the auto-drafted statement of input tax credit available to you, generated on the 14th of each month from what your suppliers filed. From the portal's Invoice Management System (IMS) you can accept, reject or keep pending supplier invoices before they flow into GSTR-2B and GSTR-3B — rejected invoices do not give you credit, so act on them early in the month. Businesses above the notified turnover threshold also report B2B invoices on the Invoice Registration Portal (IRP), which auto-fills GSTR-1.

Late fees and interest

GSTR-1 is due by the 11th of the following month and GSTR-3B between the 20th and 24th depending on your state (quarterly dates under QRMP) — see our due-date calendar for the exact schedule.

Mistakes that trigger notices

• Assuming zero sales means no filing — nil returns are mandatory
• Claiming ITC that is not in GSTR-2B — credit not reflected there gets reversed with interest and a notice
• GSTR-1 and GSTR-3B turnovers that do not match — reconcile your sales book before filing, or the mismatch invites scrutiny
• Missing the sequential order — the portal may not let you file a period until prior returns are cleared