GSTR-1 vs GSTR-3B: Difference, Due Dates and Matching

The short answer

GSTR-1 says what you sold, invoice by invoice. GSTR-3B says how much tax you owe in total and is the return through which you pay it.

Think of GSTR-1 as the detailed sales register you hand to the government, and GSTR-3B as the bill you settle every month. The first is information; the second is payment.

GSTR-1 vs GSTR-3B at a glance

	GSTR-1	GSTR-3B
What it reports	Outward supplies (sales), invoice-wise for B2B	Summary of sales, purchases (ITC) and tax payable
Level of detail	Each B2B invoice, credit note, export; B2C totals by state and rate; HSN summary	Totals by category only
Tax payment	No	Yes, through ITC and cash ledger
Input tax credit	Not reported	Claimed here, limited to GSTR-2B
Monthly due date	11th of next month	20th of next month
QRMP due date	13th of the month after the quarter	22nd or 24th of the month after the quarter (depends on your state)
Who sees it	Your buyers (via their GSTR-2B)	Only you and the department
Correction route	Amendment tables next month, or GSTR-1A before GSTR-3B	Liability via GSTR-1A; other changes in the next return

How the two returns link

The GST system chains the returns together:

1. You file GSTR-1. Your B2B invoices land in each buyer’s GSTR-2B.
2. Your suppliers file their GSTR-1. Their invoices land in your GSTR-2B, which tells you how much input tax credit you can take.
3. You file GSTR-3B. The sales liability is pre-filled from your GSTR-1; the ITC is pre-filled from your GSTR-2B. You pay the balance.

So GSTR-3B is no longer a free-form return. Its sales numbers come from GSTR-1 and its credit numbers come from GSTR-2B. If one of those is wrong, GSTR-3B is wrong.

Worked example: one month, both returns

A Gujarat wholesaler’s May 2026:

Item	Amount
Sales to registered buyers in Gujarat (taxable)	₹4,00,000 at 18% → CGST ₹36,000 + SGST ₹36,000
Sales to a registered buyer in Rajasthan	₹1,00,000 at 18% → IGST ₹18,000
Counter sales to consumers in Gujarat	₹50,000 at 18% → CGST ₹4,500 + SGST ₹4,500
Purchases in GSTR-2B (eligible ITC)	IGST ₹10,000, CGST ₹25,000, SGST ₹25,000

GSTR-1 (by 11 June): the Gujarat and Rajasthan B2B invoices go one by one into Table 4A; the counter sales go into B2CS as one line for Gujarat at 18%; the HSN summary covers all three.

GSTR-3B (by 20 June): Table 3.1(a) shows outward taxable supplies of ₹5,50,000 with IGST ₹18,000, CGST ₹40,500, SGST ₹40,500. Table 4 shows ITC of IGST ₹10,000, CGST ₹25,000, SGST ₹25,000.

Tax payable after ITC:

• IGST: ₹18,000 − ₹10,000 = ₹8,000
• CGST: ₹40,500 − ₹25,000 = ₹15,500
• SGST: ₹40,500 − ₹25,000 = ₹15,500

The wholesaler pays ₹39,000 in cash. (ITC set-off follows an order — IGST credit is used first against IGST, then CGST and SGST — so the head-wise split can differ from this simple version. The portal works it out.) Notice that GSTR-3B’s sales total is exactly GSTR-1’s total. That is the rule to keep.

You can check the tax on any amount with the GST calculator.

Why GSTR-1 and GSTR-3B mismatch

Most mismatches come from four habits:

• A credit note in one return, not the other. Sales returns reduce GSTR-1 through Table 9B; if the same credit note is not reflected in GSTR-3B’s totals, the two disagree. See credit note vs debit note.
• Invoices added after GSTR-1 is filed. A bill entered late for an earlier month appears in that month’s GSTR-3B working but not in its filed GSTR-1.
• Advances and their adjustment. Advances received for services are taxed when received and adjusted later; skipping either side creates a gap.
• Two separate sources. Sales register in one place, GSTR-1 typed by hand, GSTR-3B prepared from a summary sheet. Three sources, three answers.

The fix is structural: prepare both returns from the same set of documents, and correct GSTR-1 (through GSTR-1A or the amendment tables) rather than patching GSTR-3B.

Late fees and interest

• Late fee: generally ₹50 a day (₹25 CGST + ₹25 SGST) for each return, ₹20 a day for nil returns, capped by turnover slab.
• Interest: 18% a year on tax paid late, on the part paid in cash.
• Knock-on effects: GSTR-3B cannot be filed for a period while an earlier one is pending; a long gap can lead to the registration being suspended; and late GSTR-1 holds up your buyers’ credit.

Which returns does your business file?

Business	Returns
Regular taxpayer, turnover above ₹5 crore	GSTR-1 monthly, GSTR-3B monthly, annual GSTR-9 (and GSTR-9C where it applies)
Regular taxpayer up to ₹5 crore, monthly	GSTR-1 and GSTR-3B monthly
Regular taxpayer up to ₹5 crore, QRMP	GSTR-1 and GSTR-3B quarterly, PMT-06 monthly, optional IFF
Composition dealer	CMP-08 quarterly, GSTR-4 yearly — see composition scheme

Preparing both returns without re-typing

If your invoices, credit notes and purchase bills are already in VyapRise, the GSTR-1 and GSTR-3B reports are built from those same documents, with the HSN summary alongside. The filing desk shows the due dates, checks GSTR-1 for the errors that stop buyers’ credit, shows the cash to pay by tax head for the PMT-06 challan, and sends the files to your CA. GST reports are on the Pro plan, and the returns themselves are filed by you or your CA on the GST portal.

For the step-by-step portal process for GSTR-1, read GSTR-1 kaise bhare.

This guide reflects GST rules as of October 2026. Due dates are sometimes extended by notification; confirm each period’s dates on the GST portal or with your CA.