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GST Basics

GSTR-1 and GSTR-3B: What They Are and When to File

Two returns confuse most small business owners. Here is what each one reports, when it is due, and what happens if you file late.

Platform Owner · · 2 min read

Almost every GST-registered business files two returns. They sound similar and are often confused, but they do quite different jobs.

GSTR-1: your sales, invoice by invoice

GSTR-1 is a detailed statement of outward supplies. Every B2B invoice is listed individually, while B2C sales are summarised by state and tax rate. It also captures credit notes, debit notes, exports and an HSN-wise summary.

This return is what feeds your buyer's GSTR-2B. If you file late or wrongly, your customer cannot claim their input credit — which is why buyers chase suppliers about it.

GSTR-3B: your tax summary and payment

GSTR-3B is a self-declared summary. It reports total outward supplies, the input tax credit you are claiming, and the net tax you owe. This is the return where you actually pay.

Due dates

  • GSTR-1 (monthly) — 11th of the following month
  • GSTR-1 (QRMP, quarterly) — 13th of the month after the quarter
  • GSTR-3B (monthly) — 20th of the following month

Businesses with turnover up to ₹5 crore can opt for the QRMP scheme: file quarterly, but pay monthly.

Late filing costs more than the fee

Late fees run at ₹50 per day (₹20 for nil returns), plus 18% annual interest on unpaid tax. The bigger risk is structural — persistent late filing can get your e-way bill generation blocked, which stops you moving goods at all.

Making filing a non-event

Both returns are built entirely from invoices you have already raised. If your billing data is correct through the month, filing is a review-and-submit exercise. BikriBook generates portal-ready GSTR-1 JSON and a GSTR-3B summary from your invoices, so nothing has to be re-keyed.

Frequently asked questions

What is the difference between GSTR-1 and GSTR-3B?
GSTR-1 is an invoice-level statement of your sales. GSTR-3B is a summary return where you declare your tax liability, claim input credit and make the payment.
What is the late fee for GSTR-3B?
Late fees are ₹50 per day (₹20 per day for nil returns), plus interest at 18% per annum on any unpaid tax.
Can I revise GSTR-1 after filing?
No. GST returns cannot be revised. Corrections are made by amending the entry in a later period return.