GSTR-1 vs GSTR-3B: Differences, Due Dates and Reconciliation

Quick answer: GSTR-1 vs GSTR-3B comes down to detail versus summary. GSTR-1 reports every sale, credit note and debit note invoice by invoice, and is due on the 11th (or the 13th after the quarter for QRMP filers). GSTR-3B summarises your output tax, claims input tax credit and pays the tax, and is due on the 20th (or the 22nd or 24th quarterly).

Every regular GST taxpayer in India files these two returns, and the most common compliance problems come from treating them as separate jobs. They are linked: your GSTR-1 now drives the liability in your GSTR-3B, and your suppliers' GSTR-1 decides how much credit you can claim. This comparison covers what each return contains, the due dates, the filing order, the 2025 locking and time-bar changes, late fees and a reconciliation routine with a worked example. For a full walkthrough of the filing screens, see our guide to GST return filing in India. Every figure starts with your invoices, so make sure they are right in the first place with our free GST invoice generator.

This article is general information as of 2026, not tax or legal advice. Due dates and portal rules change by notification, so confirm them on the GST portal or with a chartered accountant.

GSTR-1 vs GSTR-3B at a glance

Point	GSTR-1	GSTR-3B
What it is	Statement of outward supplies (section 37)	Summary return with tax payment (section 39)
Level of detail	Invoice-wise for B2B, rate-wise and state-wise summaries for B2C	Totals only
Input tax credit	Not claimed here	Claimed here, from GSTR-2B
Tax payment	None	Net tax paid by cash and credit
Monthly due date	11th of next month	20th of next month
QRMP due date	13th after the quarter (IFF optional for months 1 and 2)	22nd or 24th after the quarter, by state
Who it affects	Your buyers' GSTR-2B and their credit	Your own liability and credit ledger
Corrections	GSTR-1A before GSTR-3B, or amendment tables later	Adjust in a later GSTR-3B
Late fee	Rs 50 per day, Rs 20 for nil, capped	Rs 50 per day, Rs 20 for nil, capped, plus 18% interest on late tax

What is GSTR-1?

GSTR-1 is your sales statement. It lists:

• B2B invoices to registered buyers, invoice by invoice with the buyer's GSTIN.
• Large B2C inter-state invoices above the threshold, individually.
• Other B2C sales, summarised by rate and state.
• Exports and SEZ supplies, with or without tax. Exports under an LUT in GST go here as without payment of tax.
• Credit notes and debit notes, explained in our credit note guide.
• Advances received and adjusted, nil-rated, exempt and non-GST supplies, including sales on a bill of supply.
• An HSN-wise summary using the HSN and SAC codes on your invoices, and a document summary of serial numbers issued.

If you issue e-invoices because your turnover is above the India e-invoice limit, the IRN data auto-fills much of GSTR-1. Once filed, B2B records flow to your buyers' Invoice Management System and GSTR-2B.

What is GSTR-3B?

GSTR-3B is the return where tax is settled. Its main tables are:

• Table 3.1: outward supplies and tax, including zero-rated and exempt supplies and inward supplies under reverse charge.
• Table 3.2: inter-state supplies to unregistered persons, composition dealers and UIN holders, by state.
• Table 4: input tax credit available, reversed and net, auto-filled from GSTR-2B. Our guide to input tax credit under GST explains what belongs here.
• Table 5: exempt, nil-rated and non-GST inward supplies.
• Table 6: payment of tax, interest and late fee, using the credit ledger first and cash for the balance.

The IMS changes credit flow too. You act on supplier records in the GST Invoice Management System, GSTR-2B is generated on the 14th, and Table 4 is filled from it.

GSTR-1 and GSTR-3B due dates in 2026

Filer type	GSTR-1	GSTR-3B	Tax payment
Monthly (turnover above Rs 5 crore, or by choice)	11th of next month	20th of next month	With GSTR-3B
QRMP, months 1 and 2 of the quarter	IFF optional, 1st to 13th of next month	No return	PMT-06 by the 25th of next month
QRMP, end of quarter	13th of month after quarter	22nd or 24th of month after quarter, depending on state group	With GSTR-3B

For example, the September 2026 GSTR-1 for a monthly filer was due on 11 October 2026 and GSTR-3B on 20 October 2026. For a QRMP filer, the July to September 2026 quarter's GSTR-1 was due on 13 October 2026 and GSTR-3B on 22 or 24 October 2026. The government extends dates by notification from time to time, so check the portal's return calendar.

Filing order, the GSTR-3B lock and GSTR-1A

The order is no longer a matter of habit. GSTN made the outward liability that GSTR-3B auto-fills from GSTR-1, GSTR-1A and IFF non-editable from the July 2025 tax period. If a sale is missing or wrong in GSTR-1, you cannot fix it by typing a different figure in GSTR-3B. Instead:

1. File GSTR-1 for the period by its due date.
2. Review the auto-filled GSTR-3B liability against your sales register.
3. If something is wrong, file GSTR-1A for the same period to add or amend records. GSTR-1A is available after GSTR-1 is filed and before GSTR-3B for that period.
4. Review Table 4 credit against GSTR-2B and your purchase register.
5. Pay any cash balance and file GSTR-3B.

The portal also enforces sequence in the other direction: GSTR-1 for a period cannot be filed while GSTR-3B for the previous period is pending, and GSTR-2B is not generated for a taxpayer whose previous GSTR-3B is outstanding.

The three-year time bar

The Finance Act, 2023 bars filing GSTR-1, GSTR-3B, GSTR-9 and several other returns after three years from their due date. GSTN issued a series of advisories through 2024 and 2025 and then began blocking time-barred returns on the portal. A return that is time-barred cannot be filed at all, which can leave a registration in default with no way to regularise it, so clear any pending returns early.

Late fees and interest

Late fees apply to both returns, at Rs 50 per day (Rs 25 CGST and Rs 25 SGST) and Rs 20 per day for nil returns. Notification 19/2021-Central Tax capped the GSTR-3B late fee; the central tax caps are Rs 250 for nil returns, Rs 1,000 for turnover up to Rs 1.5 crore, Rs 2,500 for turnover from Rs 1.5 crore to Rs 5 crore, and Rs 5,000 above that. Doubling for SGST gives combined caps of Rs 500, Rs 2,000, Rs 5,000 and Rs 10,000. You can read the text of Notification 19/2021-Central Tax on the GST Council site. GSTR-1 has matching caps under a separate notification.

Late GSTR-3B also means late tax, and section 50 charges interest at 18% a year on the tax paid late in cash.

Worked example: reconciling one month

A Delhi agency files monthly. For October 2026 its sales register shows:

Item	Taxable value	GST at 18%
Tax invoices issued	Rs 12,00,000	Rs 2,16,000
Credit note for a cancelled project	minus Rs 1,00,000	minus Rs 18,000
Net output tax	Rs 11,00,000	Rs 1,98,000
Eligible ITC in GSTR-2B		Rs 1,20,000
Cash payable		Rs 78,000

When the accountant files GSTR-1 on 11 November and opens GSTR-3B, Table 3.1 shows output tax of only Rs 1,89,000. Comparing the two, she finds one invoice of Rs 50,000 (Rs 9,000 tax) that was left out of GSTR-1. Rs 1,98,000 minus Rs 9,000 is Rs 1,89,000, which explains the gap. Because the liability is locked, she adds the missing invoice through GSTR-1A, the GSTR-3B liability updates to Rs 1,98,000, and she pays Rs 78,000 in cash.

Suppose instead the agency filed GSTR-3B 10 days late. The late fee would be 10 days at Rs 50 = Rs 500, well within the cap. Interest at 18% a year on the Rs 78,000 cash paid late would be Rs 78,000 x 18% x 10 / 365 = about Rs 385. Small amounts, but they repeat every month a business is late, and the missing invoice would still have to be fixed.

A monthly reconciliation routine

1. Lock your sales register for the month once all invoices, credit notes and debit notes are entered, with no gaps in your invoice number series.
2. Compare register totals by rate, by B2B and B2C, and by state with the GSTR-1 summary before you file it.
3. After filing, compare GSTR-1 with the auto-filled GSTR-3B Table 3.1 and use GSTR-1A for any corrections.
4. Reconcile GSTR-2B with your purchase register and remove blocked or ineligible credit.
5. Match the cash paid in GSTR-3B to your bank statement as part of your month-end close.
6. Track errors that need a later adjustment, and fix the underlying invoice using the steps in how to correct an invoice.

Why the two returns drift apart

Most mismatches have a short list of causes, and knowing them speeds up the monthly check:

• Late additions. An invoice raised after the books were closed reaches GSTR-1 next month but was never in this month's liability.
• Credit notes. A credit note recorded in the books but not reported in GSTR-1, or reported against the wrong period.
• Advances. Tax paid on advances for services in GSTR-3B but the advance table left blank in GSTR-1, or adjustments missed when the invoice is issued.
• Classification errors. A B2B sale entered as B2C because the buyer's GSTIN was missing, or an inter-state sale shown as intra-state.
• Rate errors. Old rates used after the GST 2.0 changes from 22 September 2025.

The department watches these gaps. Rule 88C allows the system to send an intimation when the liability in GSTR-1 exceeds what was paid through GSTR-3B by more than the prescribed limits, and the taxpayer must pay the difference or explain it, or face restrictions on filing the next GSTR-1. Rule 88D does the same for credit claimed in GSTR-3B beyond what GSTR-2B supports. Monthly reconciliation keeps you well clear of both.

Which return matters more?

Both, for different people, and the answer does not change with business size. GSTR-1 matters most to your customers, because their credit depends on it; file it late or wrongly and they will chase you or withhold payment. GSTR-3B matters most to you, because it settles your liability, carries the interest and decides your own credit. A clean GSTR-1 makes GSTR-3B almost automatic, and a GSTR-3B that matches GSTR-1 keeps notices away. Small businesses that hand returns to an accountant should still review the GSTR-1 summary and the auto-filled GSTR-3B before each filing, because the accountant can only report the invoices they are given.

Start with accurate GST invoices

The GSTR-1 vs GSTR-3B question is really about one data trail: invoices go into GSTR-1, GSTR-1 drives GSTR-3B, and GSTR-3B settles the tax. Get the invoice right and both returns follow. Create GST invoices with GSTINs, HSN codes and the correct CGST, SGST or IGST split using our free invoice generator, and keep every period reconciled before you file. Your finished invoice downloads as a PDF, free and with no sign-up.