Glossary
What is GSTR-1?
The return that tells the government, and your buyers, what you sold.
Updated
In short
GSTR-1 is the GST return in which a registered business reports its outward supplies, monthly or quarterly. SimpleERP does not file it, but its sales register and HSN summary give your accountant every figure needed to file.
GSTR-1 is the GST return in which a registered business reports its outward supplies: B2B invoices one by one, B2C sales in summary, credit and debit notes, an HSN-wise summary and a count of documents issued. It is filed monthly or quarterly. The B2B details flow to buyers' GSTR-2B statements, so a mistake in your GSTR-1 can cost your customers their input tax credit.
GSTR-1: a worked example
In September 2026 Lakshmi Steel Furnitures billed ₹3,39,400 of taxable sales, including INV-2026-27-0213 to Ravi Stores (GSTIN 33ABCPR4821K1ZN) for ₹9,980. Assuming 18% on everything, its GSTR-1 for September would report output tax of ₹61,092. Rates change, so confirm the rate for your goods with your CA or the GST portal before you rely on it.
| GSTR-1 section | What goes in | Lakshmi Steel, September |
|---|---|---|
| B2B invoices | Each invoice to a registered buyer | INV-2026-27-0213, Ravi Stores, ₹9,980 |
| B2C (small) | Sales to unregistered buyers, by state and rate | Walk-in sales in Tamil Nadu |
| Credit and debit notes | Notes against registered buyers | Any returns in the month |
| HSN summary | Totals by HSN code and rate | 9403, 9401, 9405, 7308 |
FAQ
Questions, answered
What is the due date for GSTR-1?
For monthly filers, the 11th of the following month. Businesses with turnover up to ₹5 crore can opt for quarterly filing under the QRMP scheme, with GSTR-1 due on the 13th of the month after the quarter. Dates can be extended by notification, so check the portal.
What is the difference between GSTR-1 and GSTR-3B?
GSTR-1 is the detail of your sales, invoice by invoice. GSTR-3B is the summary in which you declare total sales, claim input tax credit and pay the tax. The sales in both should agree, and the portal flags large gaps.
Can I correct a GSTR-1 after filing it?
A filed GSTR-1 cannot itself be corrected. You amend the wrong invoice in a later GSTR-1 through the amendment tables, within the time limit for that financial year. Fix the invoice in your books first, usually with a credit or debit note.
Do I need to report every B2C invoice separately?
B2C invoices are not all reported separately in GSTR-1. Sales to unregistered buyers are reported in summary by state and rate. Only large inter-state B2C invoices above the notified limit are reported one by one. B2B invoices are always reported individually so buyers see them.
Related
Keep reading
GSTR-3B
The summary GST return where you declare sales, claim credit and pay the net tax.
Read moreHSN code
The number that classifies goods for GST and customs, and so decides their GST rate.
Read moreGST compliance
Place of supply, HSN summary, registers and the input tax summary, and what is not included.
Read more
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