GSTR-1 vs GSTR-3B: Key Differences Every Business Owner Must Know

If you're registered under GST, you file both GSTR-1 and GSTR-3B every month. But most business owners don't understand the difference — and that confusion leads to notices and penalties.

The short version

What goes in GSTR-1?

GSTR-1 is your outward supply statement — a list of all invoices you've raised to customers during the month. It is divided into:

• B2B invoices (Table 4): Sales to other GST-registered businesses. Your buyer uses this to claim ITC.
• B2C large invoices (Table 5): Sales to consumers above ₹2.5 lakhs (inter-state).
• B2C others (Table 7): All other consumer sales, by state.
• Export invoices (Table 6): Zero-rated exports.
• Credit/debit notes (Table 9/10): Amendments to previous invoices.

What goes in GSTR-3B?

GSTR-3B is the monthly summary return where you declare your total liability and pay the tax. It contains:

• Section 3.1: Outward supply summary (taxable, nil-rated, exempt, zero-rated)
• Section 3.2: Inter-state supplies to unregistered/composition dealers
• Section 4: ITC available and ITC claimed (from GSTR-2B)
• Section 5: Exempt, nil-rated and non-GST supplies
• Section 5.1: Interest and late fee payable
• Section 6.1: Net tax payable (IGST, CGST, SGST, Cess)

Why GSTR-1 and GSTR-3B must match

The GST department cross-checks your GSTR-1 (what you reported selling) against your GSTR-3B (what you declared as taxable). If there's a mismatch, you'll receive a scrutiny notice. The most common mismatch: sales reported in GSTR-1 are higher than GSTR-3B. This triggers ASMT-10 notices.