Which of Tables 9A, 9C and 10 takes a correction, what cannot be changed, where GSTR-1A fits, and the 30 November deadline in section 37(3).
An amendment corrects an earlier month, never this one
When something in a GSTR-1 was wrong, the way to put it right depends on when you find it. A document of the month you are about to file is corrected in that month’s own tables before you file; that is not an amendment, and the offline tool will not amend it. An amendment restates a document already furnished in an earlier month’s GSTR-1, and goes in the GSTR-1 you are filing now.
An invoice left out of an earlier month altogether is not an amendment either: nothing was filed to correct, so it is declared late, as an ordinary invoice in this return, under the same deadline. fynxIQ holds the return until you answer for each row of your own sales register dated in an earlier month, declare it late here or leave it out, because declaring one its own month already carried pays the tax twice; past the deadline, the row cannot go in at all. A month that carries an amendment is not a nil month either.
Everything after that turns on the original document’s date. It fixes the document’s period and its financial year, and the financial year fixes the deadline.
Each kind of correction has a table of its own
The amendment tables mirror the tables of original supplies:
- Table 9A: an invoice to a registered buyer (B2BA), a large invoice to a consumer in another state (B2CLA), or an export invoice (EXPA).
- Table 9C: a credit or debit note already reported, to a registered buyer (CDNRA), or to a consumer or on an export (CDNURA).
- Table 10: consumer sales that went into Table 7 as totals, restated for one earlier month and one state, rate by rate.
An amendment row is the document as it now stands
Table 9B is not an amendment table: it takes a new credit or debit note, even one against an earlier month’s invoice. A note is amended in 9C only when the note itself was reported wrongly.
Every amendment row is the document as it now stands, with the number and date it was first filed under, and the portal replaces what was filed with it. An invoice filed at ₹10,000 that should have been ₹12,000 is amended to ₹12,000, not by ₹2,000. A Table 10 row names the financial year and month it restates and carries that month’s new figures for the state and rate, not the change.
An amendment carries the rate in force when the original supply was made, as a credit or debit note against it does. 12% ceased to be a general rate on 22 September 2025 (Notification 9/2025-Central Tax (Rate)) and 28% ceased to be a GST rate on 1 February 2026 (Notification 19/2025-Central Tax (Rate)), yet an August 2025 invoice at 12% amended in the November 2025 return stays at 12%. fynxIQ accepts a rate withdrawn since on an amendment without a warning; on a fresh invoice of the month the same rate is a warning, never a blocker.
The Returns Offline Tool user manual names three fields its amendment sheets will not let change: the buyer’s GSTIN on B2BA, the original place of supply on B2CLA, and the export type on EXPA. GSTN’s FAQ on GSTR-1A says a buyer’s GSTIN can be corrected only through a later period’s GSTR-1. fynxIQ’s form takes one buyer GSTIN, the one the invoice was filed under, so it cannot carry a change of buyer.
The deadline is 30 November, or the annual return if that comes first
Section 37(3) of the CGST Act, first proviso, as amended by the Finance Act 2022 (Notification 18/2022-Central Tax), from 1 October 2022, lets an error or omission in a GSTR-1 be rectified in a later return, but not after 30 November following the end of the financial year the details belong to, or the furnishing of the annual return for that year, whichever is earlier.
The financial year is the original document’s. An invoice of March 2026 can be amended until 30 November 2026; one of April 2026 until 30 November 2027. A GSTR-1 is filed after its month ends, so for a monthly filer the October return is the last that can carry an amendment to the year that ended in March, and only if it is filed by 30 November; the November return cannot be filed before 1 December. File the annual return earlier and the window shuts that day.
fynxIQ judges each amendment against the first day the return can be filed, the day after its period ends. When that day is past the original’s 30 November, the amendment is a blocker and the GSTR-1 JSON is held, since the portal would refuse the row; fynxIQ says to take it out, and that what the law no longer allows in a GSTR-1 is a question for your accountant. While the window is open, the Every check tab names the date by which this return must be filed, and the annual return as what can close the window sooner, without guessing whether you have filed it.
fynxIQ does not hold the earlier return either. It checks the new figures against themselves and the original’s date against the deadline; it cannot say whether the original was filed as the amendment says, or what the change does to the tax.
GSTR-1A fixes this month’s GSTR-1 before the GSTR-3B
Notification 12/2024-Central Tax of 10 July 2024 added a proviso to rule 59(1) of the CGST Rules and Form GSTR-1A: after filing the GSTR-1 for a period and before filing the GSTR-3B for it, you may amend that GSTR-1 or add what it missed. GSTR-1A opens on the GSTR-1’s due date or the day the GSTR-1 is filed, whichever is later, and closes when the GSTR-3B for the period is filed. What it carries reaches that GSTR-3B with the GSTR-1.
GSTN’s FAQ on GSTR-1A sets the limits. It is optional and filed once for a period, online or through a GSP, not from the offline tool. It covers only the current period’s GSTR-1, a quarterly filer’s IFF included; an earlier period is amended in a later GSTR-1, under the deadline above. A buyer’s GSTIN cannot be changed in it. And a record saved in GSTR-1A but not filed stops the GSTR-3B until you file, delete or reset it.
Since the July 2025 tax period the liability the portal fills into Table 3.1 of the GSTR-3B from the GSTR-1 and GSTR-1A cannot be overtyped, and since the November 2025 tax period neither can Table 3.2, the inter-state supplies to unregistered persons, composition taxpayers and UIN holders (GSTN advisories of 7 June 2025 and 5 December 2025). A wrong outward figure is changed in GSTR-1A before the GSTR-3B, or in a later GSTR-1 as an amendment, not by editing the 3B.
fynxIQ does not prepare a GSTR-1A. If you change a figure there, the portal’s GSTR-3B carries it and fynxIQ’s GSTR-3B draft, built from the GSTR-1 fynxIQ prepared, does not. Drop the portal’s GSTR-3B PDF beside the draft and the row-by-row comparison shows the difference in Table 3.1.
The Amendments tab takes one typed by hand
On the return’s Amendments tab an amendment is typed by hand, or read from the offline tool’s workbook with its amendment sheets, b2ba to b2csa, filled. To type one:
- Choose Add an amendment, then what you are correcting: one of three kinds of invoice for Table 9A, one of two kinds of note for Table 9C, or consumer sales of an earlier month for Table 10.
- For an invoice or a note, enter its number and date as filed, the number and date now if either changed, and the document as it now stands, one rate line at a time. The invoice or note value is suggested from the lines.
- For Table 10, choose the month being corrected from the twenty-four before the one being filed, the state, and the operator’s GSTIN if the sales went through one.
- Choose Add to the return. Anything missing or unreadable is marked beside its field, by the same checks that decide whether the entry goes into the return.
- Read the Every check tab for the deadline. A deadline blocker, or one about a typed amendment, is shown on the Amendments tab as well.
fynxIQ keeps what you type, and leaves some corrections to you
When the GSTIN is one of your GST profiles, typed amendments are kept on fynxIQ’s server with the client and the month, and come back when the return is opened again; one the server has not taken yet is marked Not kept yet, with a button to keep it. Otherwise they stay on the page only, and the tab says so. The table under them is each amendment as the JSON carries it. A document amended both by hand and in an uploaded workbook is carried once, from the workbook, and the return is held until you remove one of the two.
fynxIQ does not prepare Table 14A, which amends supplies made through an operator. A workbook row for Table 10 that moves supplies between states is stopped, because the JSON has one place of supply for it; enter that row on the portal. Amendment rows in Flipkart’s report for GSTR-1 and GSTR-8 filing (sections 10A(1) and 10B(1)) are not turned into Table 10 rows: fynxIQ stops the return and says how many there are, for you to enter on the portal against the period Flipkart names. And it does not file: you upload the JSON on the portal and submit with your DSC or EVC.
Try it on your own figures with the free GSTR-1 JSON validator.
Which file to download, and from where: the list for each marketplace and the GST portal.
By Raunak Pathak, founder of fynxIQ, who files GST returns on it. Last updated 15 October 2026. This is general information about how GST returns work, not advice about your particular return.