Skip to content
399apps.com logo 399apps.com
Get a demo
GST returns guide

How to file GSTR-1: a step-by-step guide

Short answer

GSTR-1 is the monthly or quarterly GST return where you report all outward supplies (sales). To file it, log in to the GST portal, open the Returns Dashboard, select the period, add your B2B, B2C, export and credit/debit-note details (or upload them in bulk), generate the summary, then submit with a DSC or EVC.

Updated 2026-06-03 · 399Apps · General GST information, not tax advice

How to file GSTR-1 on the GST portal: step by step

You file GSTR-1 online at gst.gov.in. The same steps apply whether you file monthly or quarterly under QRMP.

  1. 1

    Log in to the GST portal

    Go to gst.gov.in, log in with your credentials, and open Services → Returns → Returns Dashboard.

  2. 2

    Select the return period

    Choose the financial year and the month or quarter, then click "Prepare Online" (or "Prepare Offline" for bulk upload) under the GSTR-1/IFF tile.

  3. 3

    Add your outward supplies, table by table

    Enter invoice details: Table 4 (B2B), Table 5 (large inter-state B2C), Table 6 (exports), Table 7 (consolidated B2C), Table 9B (credit/debit notes), Table 12 (HSN summary) and Table 13 (documents issued).

  4. 4

    Upload in bulk (optional)

    For high invoice volume, generate a JSON from the GST Offline Tool or your accounting software and upload it instead of keying invoices one by one.

  5. 5

    Generate the summary and preview

    Click "Generate GSTR-1 Summary", then open the preview to check totals and fix any errors before you file.

  6. 6

    Submit and file

    File with a Digital Signature Certificate (companies/LLPs) or EVC (OTP). Once filed, your B2B values flow into your buyers’ GSTR-2B and auto-populate your own GSTR-3B liability.

What is GSTR-1?

GSTR-1 is a return that captures every outward supply (sale) a GST-registered business makes in a tax period — B2B and B2C invoices, exports, credit and debit notes, and advances. It is the source document that feeds the GST system: the data you report here populates your customers’ input-tax-credit statement (GSTR-2B) and pre-fills your own summary return (GSTR-3B).

Because GSTR-1 drives ITC for your buyers, accuracy matters — a missed or wrong invoice can block your customer’s credit and trigger reconciliation queries.

Who must file GSTR-1 and when (due dates)

Every regular GST-registered taxpayer must file GSTR-1, even for a nil period. Your frequency depends on turnover and the QRMP scheme:

  • • Monthly filers: due by the 11th of the following month.
  • • Quarterly (QRMP) filers — turnover up to ₹5 crore: GSTR-1 due by the 13th of the month after the quarter.
  • • QRMP taxpayers can optionally upload B2B invoices in the first two months of a quarter using the Invoice Furnishing Facility (IFF), due by the 13th.
  • • Composition dealers file CMP-08/GSTR-4 instead, not GSTR-1.

Details and documents you need

Before you start, keep your sales invoices, export and SEZ documents, advance receipts and adjustments, and any credit/debit notes for the period ready. You will also need the correct HSN/SAC codes and tax rates for each item, plus the place of supply for inter-state sales so CGST/SGST or IGST is applied correctly.

What happens after you file: GSTR-1A, GSTR-2B and GSTR-3B

After filing, the system locks most fields for the period. If you spot an error, GSTR-1A lets you amend the same period before you file GSTR-3B; otherwise corrections move to the next period’s amendment tables. Your filed B2B data appears in each buyer’s GSTR-2B (their ITC), and your outward-supply liability auto-populates GSTR-3B — so a correct, on-time GSTR-1 makes GSTR-3B faster and cleaner.

Common GSTR-1 filing mistakes to avoid

The most frequent errors are: reporting B2B invoices as B2C (which denies your buyer ITC), using the wrong place of supply (charging CGST/SGST instead of IGST), missing the HSN summary in Table 12, skipping credit/debit notes, and filing after the due date — which attracts a late fee and delays your GSTR-3B.

How 399Apps helps

Nidhi Books (by 399Apps) prepares your GSTR-1 automatically: every GST invoice you raise is tagged with the right HSN, place of supply and tax split, and the app exports a CA-ready GSTR-1 (B2B, B2C and HSN summary) you can upload to the portal — so filing is a review, not a re-entry job.

Start your free 14-day trial See pricing
FAQ

How to file GSTR-1 — frequently asked questions

What is the due date for GSTR-1? +
Monthly filers must file GSTR-1 by the 11th of the following month. Quarterly (QRMP) filers with turnover up to ₹5 crore file by the 13th of the month after the quarter, with optional IFF uploads in the first two months.
Is GSTR-1 mandatory if there are no sales? +
Yes. A regular taxpayer must file a nil GSTR-1 even with no outward supplies in the period. You can file a nil return quickly on the portal or by SMS, but skipping it still attracts a late fee.
Can I revise GSTR-1 after filing? +
GSTR-1 cannot be revised once filed, but you can correct errors. Use GSTR-1A to amend the same period before filing GSTR-3B, or report the correction in the amendment tables (9A/9C) of a later period.
What is the difference between GSTR-1 and GSTR-3B? +
GSTR-1 is a detailed, invoice-level statement of outward supplies. GSTR-3B is a summary return where you declare total supplies, claim input tax credit and pay net GST. GSTR-1 data now auto-populates much of GSTR-3B.
What happens if I file GSTR-1 late? +
Late filing attracts a late fee of ₹50 per day (₹20 per day for nil returns), split between CGST and SGST and subject to turnover-based caps. It also delays your buyers’ input tax credit and your own GSTR-3B.

Related

Try 399Apps

GST billing, returns & e-invoicing — done automatically

Nidhi Books raises GST-compliant invoices and prepares GSTR-1 and GSTR-3B exports, with unlimited users from ₹399/month for your first app (+₹99/month per add-on, prices exclude GST). Free for 14 days.

Start your free 14-day trial Get a free demo