Most explanations of GSTR-1 are written for the person filing it. This one is written for the person on the other end, the accountant who reconciles GSTR-2B every month and wants to know why an invoice is, or is not, in it. The short version: GSTR-2B is your suppliers’ GSTR-1 data, reshaped for you. If you understand what goes into GSTR-1 and when, most “missing invoice” questions answer themselves.
What GSTR-1 is
GSTN describes Form GSTR-1 as a monthly or quarterly statement of outward supplies, furnished by all normal and casual registered taxpayers making outward supplies of goods or services or both. The legal basis is Section 37 of the CGST Act: the details of invoices, debit notes, credit notes and revised invoices issued for the period are furnished electronically, and they are then communicated to the recipient. Rule 59 prescribes the form and manner.
Three behaviours of GSTR-1 matter for everything below.
- It is a statement, not a payment return. It reports sales. The tax is declared and paid in GSTR-3B. The two are compared in GSTR-1 vs GSTR-3B.
- It must be filed even with no sales. GSTN says a nil GSTR-1 is required where there was no business activity in the tax period.
- It stays editable until filed. GSTN says invoices can be modified or deleted any number of times until the form is submitted. After filing, corrections go through GSTR-1A or the amendment tables of a later period.
Who files it and who does not
Section 37(1) applies to every registered person other than an Input Service Distributor, a non-resident taxable person, and a person paying tax under section 10 (composition), section 51 (tax deducted at source) or section 52 (tax collected at source). If your supplier is a composition dealer, there is no GSTR-1 behind the bill and nothing reaches your GSTR-2B from it.
A taxpayer can opt for the quarterly return (QRMP) if turnover in the preceding financial year was up to ₹5 crore. A quarterly filer files GSTR-1 once a quarter, and may use the invoice furnishing facility (IFF) in the first two months to pass credit to recipients early. That is covered in the QRMP section below.
When it is due
| Filer type | Due date | Example |
|---|---|---|
| Monthly | 11th of the next month | September 2026: 11 October 2026 |
| Quarterly (QRMP) | 13th of the month after the quarter | July to September 2026: 13 October 2026 |
| IFF for month 1 or 2 of a quarter (optional) | 13th of the next month | July 2026 IFF: 13 August 2026 |
GSTN’s own answer adds “or such other dates as may be extended by Government through notification”, so confirm the date if a notification has been issued for your period. The late fee for missing the date is a separate page: GSTR-1 late fee and due dates.
What is inside GSTR-1: the tables
The live form is organised in tiles. The table below uses the tile names from GSTN’s manual and adds the column that matters to a buyer: whether the rows end up in a recipient’s GSTR-2B. Confirm tile names on the live form, because GSTN has changed some of them over time, for example the HSN tile (from May 2025 it is furnished separately for B2B and B2C).
| Table | What it holds | What it means for a buyer |
|---|---|---|
| 4A, 4B, 4C, 6B, 6C | B2B invoices: supplies to registered persons | Becomes a row in the buyer’s GSTR-2B, B2B sheet |
| 9B (registered) | Credit and debit notes issued to registered recipients | Becomes a row in the CDNR sheet |
| 9A, 9C | Amendments to earlier B2B invoices and credit/debit notes | Appears in the B2BA and CDNRA sheets: check whether it replaces a row you already matched |
| 5A, 5B | B2C large: inter-State supplies to consumers above ₹1 lakh per invoice (from the August 2024 tax period) | No registered buyer, so no GSTR-2B row |
| 7 | B2C others: consolidated supplies to consumers | No registered buyer, so no GSTR-2B row |
| 6A | Export invoices | No GSTR-2B row |
| 8A to 8D | Nil-rated, exempted and non-GST supplies | Not an ITC document |
| 11A, 11B | Advances received and their adjustment | Not an invoice-level 2B row |
| 12 | HSN-wise summary of outward supplies | Summary only |
| 13 | Documents issued during the period (mandatory) | Summary only |
| 14, 15 | Supplies through e-commerce operators and under section 9(5) | Outside the four GSTR-2B sheets this guide covers: check GSTN for how they appear |
The right-hand column is our reading of how the tables line up with the four GSTR-2B sheets (B2B, B2BA, CDNR, CDNRA) that the GSTN Excel carries. GSTN’s IFF FAQ confirms the pairing for the facility: tables 4A, 4B, 4C, 6B, 6C are B2B invoices, 9B is credit and debit notes (registered), 9A is amended B2B (B2BA) and 9C is amended credit and debit notes (CDNRA). The rows that concern consumers, exports and nil-rated sales feed the seller’s own GSTR-3B liability tables instead.
Two details help when reading a supplier’s documents. Taxpayers who generate e-invoices see tables 4A, 4B, 4C, 6B, 6C, 6A and 9B auto-populated from the Invoice Registration Portal, and can edit them. And the HSN digits required are a minimum of 4 if aggregate turnover is up to ₹5 crore and 6 if it is above, so a short HSN on a supplier’s invoice is not always an error on their side.
How a GSTR-1 row reaches your GSTR-2B
GSTN describes GSTR-2B as an auto-drafted ITC statement generated for every registered person on the basis of the information furnished by suppliers in their GSTR-1, IFF and GSTR-1A. Section 38(1) of the Act says the supplier’s outward details and a statement of ITC are made available electronically to the recipient.
The cut-off logic is in Rule 60(7). For a supplier who files monthly, your GSTR-2B for a month carries the GSTR-1 details furnished between the day after the previous month’s GSTR-1 due date and the GSTR-1 due date of the month itself. The portal generates the statement on the 14th (see what GSTR-2B is). Put together:
A GSTR-1 filed after its due date misses that window and falls into the next month’s window. The invoice then reaches your GSTR-2B a month later. Why that matters in law: Section 16(2)(aa) and Rule 36(4) allow ITC only if the supplier has furnished the invoice in GSTR-1 (or IFF) and the details have been communicated to you in GSTR-2B. The freeze-date mechanics are in the freeze-date guide and the full month in the generation timeline guide.
Worked example: one supplier, two filing dates
A packaging supplier in Nashik reports two invoices and one credit note to your firm for September 2026. All three are at 18 per cent, split equally between CGST and SGST.
| Document | GSTR-1 table | Taxable value | GST | CGST + SGST |
|---|---|---|---|---|
| Invoice PK/0412 | 4A | ₹1,50,000 | ₹27,000 | ₹13,500 + ₹13,500 |
| Invoice PK/0431 | 4A | ₹2,50,000 | ₹45,000 | ₹22,500 + ₹22,500 |
| Credit note CN/0007 | 9B | ₹20,000 | ₹3,600 | ₹1,800 + ₹1,800 |
| Net ITC to your firm | ₹68,400 |
The arithmetic: ₹27,000 + ₹45,000 = ₹72,000 on the invoices, and ₹72,000 − ₹3,600 = ₹68,400 after the credit note. GSTR-3B Table 4(A)(5) is populated on a net basis from GSTR-2B, which is why the credit note reduces the figure.
| Supplier files GSTR-1 on | Reaches your GSTR-2B for | Earliest GSTR-3B that can claim it |
|---|---|---|
| 10 October 2026 (before the 11th) | September 2026, generated 14 October 2026 | September return, due 20 October 2026 |
| 15 October 2026 (after the 11th) | October 2026, generated 14 November 2026 | October return, due 20 November 2026 |
In the second case ₹68,400 of credit that your books show in September cannot be claimed in the September return. Claiming it anyway would put the GSTR-3B ITC above GSTR-2B, the situation that can trigger a DRC-01C intimation. The supplier has done nothing unusual; the invoice is simply a month late. Your move is to keep it out of September, and chase the supplier so it is not late again: see what to do when a supplier does not file GSTR-1.
If your supplier is a quarterly filer
A QRMP supplier files GSTR-1 once a quarter, on the 13th after the quarter ends. To pass credit to buyers earlier, the supplier may use IFF in months 1 and 2, for B2B invoices and credit or debit notes only, up to a cumulative ₹50 lakh in each month, by the 13th of the next month. GSTN says invoices saved, submitted or filed in IFF flow to the recipient’s GSTR-2A and, once filed, to GSTR-2B. IFF is optional, and GSTN says no late fee applies to it. If the supplier skips IFF, nothing from that month reaches your GSTR-2B until the quarterly GSTR-1. This is a frequent reason a long-standing supplier seems to vanish for two months of every three.
Amendments and GSTR-1A
A supplier who finds an error after filing has two routes. GSTR-1A is an optional facility that can be filed only once for a tax period, any time after GSTR-1 and before GSTR-3B of that period. GSTN’s example shows that ITC for a record added through GSTR-1A reaches the recipient in the next period’s GSTR-2B. Later errors go through the amendment tables, and GSTN says rectification for invoices of the previous financial year is not allowed after 30 November of the following financial year. For the recipient’s view of an amended invoice, see amended invoices, GSTR-1A and IMS.
Common mistake: treating “the supplier filed GSTR-1” as “the credit is mine”. GSTR-2B proves the invoice was reported, not that the tax was paid or that you received the goods. Section 16(2) has further conditions. Check the ITC conditions before you claim.
A buyer’s routine around the supplier’s filing date
- After the 11th (13th for quarterly suppliers). Expect most B2B suppliers to have filed. A supplier who has not is the first name on the follow-up list.
- On the 14th. Download GSTR-2B and compare it with the purchase register. Invoices in books but not in GSTR-2B are either late filings, IMS Pending, or supplier errors. Handling missing invoices shows how to sort them.
- Before the 20th. Claim what is in GSTR-2B and eligible. Hold the rest for the month in which it arrives.
- Payment policy. Decide, per supplier, whether payment waits for the invoice to appear in GSTR-2B. A template is in the payment hold SOP.
Related guides
- GSTR-1 details: how to check and verify your outward supplies
- How to fix excel to json error in GSTR-1 offline tool: troubleshooting guide
- How to prepare GSTR-1 offline using the official Excel format
- GSTR-1 Table 9 and inward supplies auto-populated from 2B: rules, corrections, and reconciliation
- GSTR-1A amendment and additional liability facility: live portal filing guide before GSTR-3B
- B2C large invoice limit in GST: GSTR-1 Table 5 rules
- GSTR-1 Filing Date: monthly, QRMP and IFF Due Dates 2026
- GSTR-1A additional tax liability adjustment: portal workflow and GSTR-3B impact
Frequently asked questions
What is GSTR-1 in simple words?
GSTR-1 is the statement of outward supplies. A registered taxpayer uses it to report what was sold in a month or quarter: invoices to registered persons, summary figures for consumers, exports, credit and debit notes, advances and an HSN summary. It must be filed even when there was no business activity.
Who has to file GSTR-1?
Section 37 of the CGST Act applies to every registered person other than an Input Service Distributor, a non-resident taxable person and a person paying tax under section 10 (composition), section 51 (TDS) or section 52 (TCS). GSTN lists normal and casual taxpayers making outward supplies as the filers, and says a nil GSTR-1 is still required.
When is GSTR-1 due?
Monthly filers file by the 11th of the next month. Quarterly filers file by the 13th of the month after the quarter. GSTN adds that the dates can be changed if the Government extends them by notification, so check the current notification for the period.
How does my supplier's GSTR-1 affect my ITC?
Your GSTR-2B is built from what your suppliers furnish in GSTR-1, the invoice furnishing facility and GSTR-1A. Under Section 16(2)(aa) and Rule 36(4), you can claim ITC on an invoice only if the supplier has furnished it and the details have been communicated to you in GSTR-2B. If the supplier files late, the invoice reaches a later month's GSTR-2B and your ITC moves with it.
Is GSTR-1 the same as GSTR-2B?
No. GSTR-1 is filed by the seller and reports sales. GSTR-2B is generated for the buyer, is not filed by anyone, and is built from what suppliers have reported in their GSTR-1, IFF and GSTR-1A.
See which supplier GSTR-1 rows reached your GSTR-2B
Drop the month’s GSTR-2B (Excel or JSON) and your purchase register into gstr2bmatch.in. The report puts each invoice in a bucket: matched, value mismatch, in books but missing from 2B, in 2B but not in books, with IMS Pending flagged separately, and totals the ITC at risk in rupees. That shows you which suppliers have not filed or filed late. It does not read GSTR-1 itself. Your GSTR-2B and purchase register files are read in your browser and never uploaded to any server.
Next in this series: GSTR-1 late fee and due dates, how to file GSTR-1 step by step, and GSTR-3B meaning and how GSTR-2B feeds it.
Last checked: 1 Oct 2026. Sources: GSTN GSTR-1 FAQ, GSTN manual: Creation of Outward Supplies Return in GSTR-1, GSTN IFF FAQ, GSTN manual: viewing Form GSTR-2B, CGST Act, Section 37, Section 38, CGST Rules, Rule 59, Rule 60, Rule 36, Section 16.