GSTR-1A: correcting your GSTR-1 after you've filed it

GSTR-1A was added by Notification 12/2024-Central Tax from the July 2024 tax period. It is optional, and it fills a gap: until then, a mistake found after filing had to wait for the next month's GSTR-1.

What it does

• Amend a record you reported in this period's GSTR-1, or add a record you missed, for the same period.
• It opens once your GSTR-1 is filed, and it stays open until you file GSTR-3B for the period.
• It has no due date of its own and no late fee.

The limits

• You can file it once for a period, and a filed GSTR-1A can't be revised.
• You can't file a nil GSTR-1A.
• It only covers the current period's GSTR-1, not earlier periods.
• Once GSTR-3B is filed, use a later GSTR-1 for the correction.

What it changes elsewhere

• The changes are filled into your GSTR-3B.
• Your buyers see them in their next period's GSTR-2B, not the current one.
• If you save records in GSTR-1A and don't file it, the portal won't let you file GSTR-3B. Delete the saved records, reset the form, or file the GSTR-1A first.

Sources conflict on whether records added through the quarterly Invoice Furnishing Facility can be amended this way, so check the portal's own FAQ for that case.