GST · Glossary
GSTR-1
Monthly or quarterly return of outward supplies (sales) filed by every registered taxpayer.
GSTR-1, prescribed under Section 37 of the CGST Act, 2017 read with Rule 59 of the CGST Rules, is the return where you report all your outward supplies (invoices issued) to the GST system. Each invoice is broken into B2B (registered customers), B2CS (small unregistered customers), B2CL (large unregistered customers), exports, and credit/debit notes. The filing frequency is monthly by default; taxpayers under the QRMP scheme (turnover < Rs. 5 crore) file quarterly with monthly summary payments.
The data you file here feeds your customers' GSTR-2A and GSTR-2B — i.e., it determines whether they can claim Input Tax Credit on the GST you charged them. Late or incorrect GSTR-1 filings directly hurt your customers' ITC eligibility and damage commercial relationships.
Worked example
For Priya, a Mumbai-based designer who raised 6 B2B invoices to KA + MH clients in April 2026, GSTR-1 for that month lists each invoice in Table 4A with the client GSTIN, place of supply, and IGST/CGST/SGST split — due by 11 May 2026 (monthly filer).
Practitioner tip
File on time even if you have zero sales — nil GSTR-1 is mandatory while your GSTIN is active. Late filing blocks subsequent GSTR-3B + attracts Rs. 50/day fee (Rs. 20/day for nil).
Related Tool
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Browse all GST rates & SAC codes →Related glossary terms
- GSTR-3B — Monthly summary return where you pay GST liability and claim Input Tax Credit.
- GSTR-2B — Auto-drafted, static monthly ITC statement showing which inward supplies you can claim.
- GSTIN — 15-character alphanumeric GST registration number assigned to every GST-registered taxpayer.
- SAC (Services Accounting Code) — 6-digit code that classifies services for GST reporting (the services equivalent of HSN).
Sources
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These definitions are educational. Tax laws change annually — verify with a Chartered Accountant before making GST or income-tax decisions.