GSTR-1 is the monthly (or quarterly) summary of outward supplies — invoices, credit notes, debit notes — that every regular GST taxpayer files. For a small business owner who'd rather be running the business, the form's eight tables can feel intimidating. Here's the practical breakdown.
The eight tables that actually matter
- B2B invoices — supplies to GSTIN-registered customers. Each line is one invoice with full breakdown.
- B2CL (Business to Consumer Large) — inter-state supplies to unregistered customers where the invoice value exceeds ₹2.5 lakh. Reported invoice-by-invoice.
- B2CS (Business to Consumer Small) — everything else to unregistered customers. Reported as state-level summary, not invoice-by-invoice.
- Exports — zero-rated supplies. Distinct table because of LUT / IGST refund nuances.
- Credit / Debit Notes — adjustments to prior invoices, with linked invoice number.
- Nil-rated, Exempted, Non-GST — supplies outside the GST net.
- HSN summary — aggregate quantity + value per HSN/SAC code. Mandatory above the turnover threshold.
- Documents Issued — count of invoices, credit notes, etc. issued in the period.
Where small businesses trip up
- Wrong place-of-supply on B2B. If your customer's billing state ≠ shipping state, the place-of-supply rule matters. Ketpy Book decides this automatically based on customer state.
- Missing HSN summary. If your turnover crossed the threshold last year, you need HSN summary this year — even if you don't bill HSN-aware customers.
- Forgetting credit notes. Refunded an invoice over chat without raising a CN? GSTN catches the mismatch when the customer claims ITC.
How Ketpy Book helps
On Pro, every B2B invoice with a valid GSTIN is auto-bucketed into the right table. Inter-state vs intra-state is decided by the customer's state code at issue time. The HSN summary is rolled up from line items. You drill from any GSTR-1 row down to the source invoice and edit in place.
When you're ready to file, export JSON in the GST offline-tool format, upload to the portal, generate summary, file. Period locks the moment you click "Mark Filed".