Glossary · also called GSTR 1, GSTR1, Outward supplies return
What is GSTR-1? Outward Supplies Return Explained
GSTR-1: GSTR-1 is the GST return in which a registered business reports its outward supplies — sales — for a tax period, with B2B invoices listed individually, B2C sales summarised, plus exports, credit and debit notes and an HSN summary. Monthly filers file it by the 11th of the following month; quarterly QRMP filers by the 13th after the quarter.
Definition
GSTR-1 tells the tax system what you sold. Its B2B details flow to your customers’ auto-drafted statements (GSTR-2B), which is how they see the input tax credit available to them. If an invoice is missing or wrong in your GSTR-1, your customer’s credit is affected — so errors here quickly turn into phone calls from customers.
GSTR-1 is a statement of supplies. Tax is paid through GSTR-3B, and the two should agree.
How it works
Main sections, in outline:
- B2B invoices, each with customer GSTIN, invoice number, date, value, place of supply, rate and tax.
- B2C large inter-state invoices above the notified threshold, listed individually.
- B2C others, summarised by place of supply and rate.
- Exports, credit and debit notes, advances and amendments.
- HSN summary by HSN code.
- Documents issued — the invoice number ranges used.
Due dates, for general guidance:
| Filer type | Due date |
|---|---|
| Monthly | 11th of the following month |
| Quarterly (QRMP) | 13th of the month after the quarter; optional IFF for B2B invoices in the first two months |
An example, with illustrative numbers only: September sales of ₹48 lakh across 62 B2B invoices and ₹3 lakh of B2C sales would be reported by 11 October for a monthly filer.
Rules and dates are revised from time to time; confirm current requirements with your tax advisor.
Common mistakes
- Wrong customer GSTIN, so the customer’s credit does not appear.
- Wrong place of supply, charging CGST/SGST instead of IGST or the reverse.
- Gaps or duplicates in invoice numbering.
- HSN summary not matching invoices.
- GSTR-1 and GSTR-3B disagreeing, which invites notices.
Note that TDS deducted by customers does not reduce the invoice value reported here.
In Zaptiz
The GST agent in Zaptiz Electrical prepares GSTR-1 figures from your invoices, runs about 20 checks, gives a health score and keeps a filing calendar. In Zaptiz Construction, the GST & TDS agent runs monthly output GST checks with a filing calendar. Neither files the return — you or your advisor review and file on the GST portal.