# GSTR-1A (Amendment of outward supplies for the current tax period)

> GSTR-1A is an optional form on the GST portal for adding or correcting sales invoices of a tax period after GSTR-1 has been filed and before GSTR-3B is filed for the same period. The corrected figures then flow into GSTR-3B.

In EaseDesk: EaseDesk builds GSTR-1 from the invoices and credit notes you issued, so what you file starts from your own records and less is left to correct afterwards. GSTR-1A itself is filed on the GST portal.

## Why it matters to your business

Until 2024, a mistake noticed after filing [GSTR-1](/glossary/gstr-1) waited until the next month,
and you adjusted the tax by hand in [GSTR-3B](/glossary/gstr-3b). Now the liability in GSTR-3B
comes straight from what you reported and is locked. GSTR-1A is the one chance to put the month
right before you pay.

## How it works

As of October 2026:

- GSTR-1A was introduced by Notification 12/2024-Central Tax of 10 July 2024.
- It opens after GSTR-1 is filed (for quarterly filers, after the quarter's GSTR-1) and closes when
  GSTR-3B for the period is filed.
- You add missed documents or amend reported ones. The net effect is added to the liability shown
  in GSTR-3B.
- It is optional. If GSTR-1 was right, there is nothing to file.

## An example

A trader files GSTR-1 for September on 10 October and, on 15 October, finds an invoice of
₹1,18,000 that was left out. The trader adds it through GSTR-1A on the same day. GSTR-3B, filed on
20 October, shows the tax on it, and the customer sees the invoice in the GSTR-2B generated on
14 November.

## Common mistakes

- Filing GSTR-3B first and then looking for GSTR-1A, which has closed by then.
- Trying to correct a customer's GSTIN through GSTR-1A.
- Using GSTR-1A every month in place of checking GSTR-1 before filing.

## Questions

### When can I file GSTR-1A?

After you file GSTR-1 for a period, until you file GSTR-3B for that period. It can be filed once for each period.

### What can be changed through GSTR-1A?

You can add invoices you missed and correct details of invoices already reported, such as value, tax and place of supply. The customer's GSTIN cannot be changed there; that correction goes in the next period's GSTR-1.

### Why does GSTR-1A matter more now?

From the July 2025 tax period, the tax liability in GSTR-3B is filled from GSTR-1, GSTR-1A and the IFF and cannot be edited there. A mistake in GSTR-1 can be fixed for the same month only through GSTR-1A.

### When does my customer see an invoice added through GSTR-1A?

In their GSTR-2B for the following month, since the current month's GSTR-2B is already generated by then.

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Source: https://www.easedesk.com/glossary/gstr-1a · Updated 2026-10-02 · EaseDesk