Why this matters
If you are a registered Indian business, two filings will follow you every month: GSTR-1 and GSTR-3B. Confuse them and you risk late-fee notices, blocked input tax credit, and unhappy buyers. Get them right and the GST officer never has a reason to call.
GSTR-1 in one line
GSTR-1 is the outward-supply return. It declares every B2B and B2C invoice you raised in the period — invoice number, date, GSTIN of buyer, taxable value, CGST/SGST/IGST.
- Filed monthly (or quarterly under QRMP) by the 11th of the next month.
- Drives the GSTR-2A / 2B of your buyer — if you don't file it, your buyer cannot claim input tax credit on your invoices.
- Mistakes here annoy your customers. They will call.
GSTR-3B in one line
GSTR-3B is the summary return + tax payment. You declare the totals, claim eligible input tax credit, and pay the net cash liability.
- Filed monthly by the 20th (staggered 22nd / 24th by state).
- This is the return that actually moves money to the government.
- Late filing = ₹50/day late fee + interest on tax due.
A worked example
A retailer in Bengaluru raises ₹5,00,000 of taxable sales in March, all intra-state at 18% GST.
- GSTR-1: lists each invoice — totals show ₹5,00,000 taxable, ₹45,000 CGST, ₹45,000 SGST.
- GSTR-3B: summary shows the same outputs, plus ₹60,000 input tax credit on purchases. Net cash payable = ₹30,000.
If the retailer skips GSTR-1, every B2B buyer's GSTR-2B is short — they will not be able to claim that ₹90,000 of credit. Expect angry phone calls within a week.
Where Biliqo helps
- Every invoice you raise on Biliqo already carries the right HSN/SAC, place-of-supply and tax split.
- The Reports module exports a CA-grade GSTR-1 and GSTR-3B in JSON / CSV compatible with the GSTN offline tool.
- Reverse charge, exports with/without payment, and credit notes are all categorised correctly — no manual reclassification.
- A pre-filing checklist warns you about missing GSTINs, invalid HSNs, or invoices outside the period.
Three habits that prevent 90% of GST headaches
- Reconcile monthly, not yearly. Pull GSTR-2B every month and match against your purchases.
- Stop waiting for the 20th. Aim to file GSTR-1 by the 5th and GSTR-3B by the 15th.
- Lock the period. Once filed, Biliqo can soft-lock the period so nobody back-dates an invoice.
TL;DR
GSTR-1 = "what I sold". GSTR-3B = "what I owe". File both, file early, reconcile monthly. Biliqo does the maths so you can focus on the business.