How to File GSTR-1: A Step-by-Step Guide

Why GSTR-1 matters to your customers

GSTR-1 is the return where you report outward supplies — your sales — in detail. Unlike GSTR-3B, it lists invoices. What you file here flows into each B2B buyer’s GSTR-2B, which is what lets them claim input tax credit. File late or wrong, and your buyer’s credit is delayed — which is why B2B suppliers are judged on their GSTR-1 discipline.

B2B vs B2C invoices

Sales to registered businesses (B2B) are reported invoice-wise with the buyer’s GSTIN, because they need it for their credit. Sales to consumers (B2C) are reported as summarised totals — invoice-wise only for large inter-state invoices above the specified value. Classifying each sale correctly is the core of GSTR-1.

The main tables

• B2B invoices — each invoice with buyer GSTIN, value and tax
• B2C (large) — inter-state invoices above the threshold, invoice-wise
• B2C (others) — consolidated by rate and place of supply
• Credit/debit notes — adjustments to earlier invoices
• Exports and SEZ supplies — zero-rated, with shipping/LUT details
• HSN-wise summary of outward supplies
• Documents issued (invoice series) summary

The HSN summary

GSTR-1 requires an HSN-wise summary of what you sold, at the digit level your turnover requires. Errors here — wrong HSN, missing rows — are increasingly validated by the portal, so your billing needs to carry correct HSN from the start. Good billing software (free with our filing plan) fills this automatically.

Filing, deadlines and QRMP

Monthly filers file GSTR-1 by the 11th of the following month. Businesses under ₹5 crore who opt for QRMP file GSTR-1 quarterly, using the IFF (Invoice Furnishing Facility) to upload B2B invoices in the first two months so buyers get timely credit. We set you on the right cadence for your turnover and buyer needs.