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GST Filing10 Jan 2026 · 6 min read

How to File GSTR-1: A Simple Step-by-Step Guide for 2026

GSTR-1 is the return where you report all your outward supplies — your sales — for the month. Filing it correctly and on time keeps your buyers' input tax credit flowing and keeps you free of penalties. Here's the plain-English version.

When is GSTR-1 due?

For most businesses filing monthly, GSTR-1 is due by the 11th of the following month. Businesses under the QRMP scheme file quarterly. Late filing attracts a late fee and can block your buyer's credit, so the 11th is a date worth protecting.

What goes into GSTR-1

  • B2B invoices — sales to other GST-registered businesses, reported invoice-by-invoice.
  • B2C invoices — sales to consumers, usually reported as a summary.
  • Credit and debit notes issued during the month.
  • HSN-wise summary of goods and services sold.

Step by step

  • Reconcile your sales for the month — make sure every invoice is recorded.
  • Log in to the GST portal and open the GSTR-1 return for the period.
  • Upload or enter your B2B and B2C data (a good billing tool exports this for you).
  • Verify the auto-drafted summary matches your books.
  • Submit and file using DSC or EVC.

The easy way

BizGST Pro keeps every invoice ready and exports a GSTR-1 summary in one click, split into B2B and B2C exactly as the portal expects. Instead of compiling data on the 10th night, you file in minutes.

Stay GST-compliant without the hassle

BizGST Pro creates compliant invoices with the correct tax split automatically, tracks payments, and keeps your GSTR-1 ready. Free forever to start.

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