GSTR-1 Filing Guide — Due Dates, QRMP, IFF, Late Fees and GSTR-1A (India 2026)

1Who has to file GSTR-1

Every registered regular taxpayer files GSTR-1, including those with no sales in the period. A handful of registrations are outside it: Input Service Distributors, composition dealers (who file CMP-08 and GSTR-4 instead), OIDAR suppliers, non-resident taxable persons, and those registered only to deduct TDS or collect TCS.

There is no turnover threshold for exemption. If you hold a regular GSTIN, GSTR-1 is due whether you traded or not — a nil return is still a return, and the portal offers a one-click SMS-based nil filing for exactly this case.

2Due dates — monthly filers

If your aggregate turnover exceeds ₹5 crore, or if you have not opted into QRMP, GSTR-1 is monthly and due on the 11th of the following month. The date is fixed and the portal does not extend it except by notification.

3Due dates — the QRMP scheme

Businesses with aggregate turnover up to ₹5 crore may opt for the Quarterly Return Monthly Payment scheme. GSTR-1 is then filed once a quarter, due on the 13th of the month following the quarter.

The catch in the name is the important part: returns are quarterly but payment stays monthly. You still deposit tax for the first two months of each quarter through form PMT-06, so QRMP reduces filing work, not cash outflow.

4The Invoice Furnishing Facility (IFF) — and why quarterly filers still upload monthly

Quarterly filing creates a problem for your customers. If you only report invoices once a quarter, a buyer who purchased from you in month one waits up to three months for the credit to appear in their GSTR-2B. Most B2B buyers will not accept that.

The IFF solves it. A QRMP taxpayer may upload B2B invoices for the first two months of the quarter, by the 13th of the following month, so credit reaches the buyer without waiting for the quarterly return. The third month's invoices go in the quarterly GSTR-1 itself.

Two features of the IFF are worth knowing. It is entirely optional, and it carries no late fee — because it is not a return and simply cannot be filed after its due date. Miss the window and the invoices roll into the quarterly GSTR-1, with the delay to your buyer that implies.

5Late fees — the exact numbers

• Normal return: ₹25 per day under CGST plus ₹25 under SGST — ₹50 per day in total
• Nil return: ₹10 per day under each Act — ₹20 per day in total
• Maximum for a nil return: ₹500
• Maximum where turnover is up to ₹1.5 crore: ₹2,000
• Maximum where turnover is ₹1.5 crore to ₹5 crore: ₹5,000
• Maximum where turnover exceeds ₹5 crore: ₹10,000
• The IFF carries no late fee at all

6No interest — but a worse consequence

Unlike GSTR-3B, a late GSTR-1 attracts no interest, because no tax is paid through this return. That makes it tempting to treat as low priority. It is not.

The real cost lands on your buyer. Until your invoice appears in their GSTR-2B they cannot claim the credit, and since the credit rules were tightened they cannot simply claim it anyway. A delayed GSTR-1 means a customer funds your tax out of their working capital, and they will notice.

7Rule 59(6) — when the portal blocks you

Rule 59(6) prevents filing GSTR-1 if you have not filed GSTR-3B for the preceding period. Monthly filers are blocked after one pending GSTR-3B; QRMP taxpayers are blocked where the preceding quarter's return is outstanding.

The block is sequential, so a single missed return stalls everything after it and the arrears compound. If you are behind, clear the oldest pending period first and work forward — there is no way to skip a period.

8GSTR-1 cannot be revised — use GSTR-1A

Once filed, GSTR-1 cannot be revised. For years the only remedy was an amendment table in a later period, which left the wrong figure visible to the buyer in the meantime.

GSTR-1A changed that. It lets you correct or add details for the same tax period, provided you do so before filing GSTR-3B for that period. Used properly, the error never reaches your buyer's GSTR-2B as a mismatch.

If the GSTR-3B for the period is already filed, GSTR-1A is closed to you and the correction moves to the amendment tables (B2BA, B2CLA, CDNRA) of a subsequent GSTR-1.

9The three-year cutoff

A GSTR-1 cannot be filed more than three years after its original due date. Once that window closes the return is barred permanently, the outward supplies can never be regularised, and the credit is lost to your buyer for good. Old pending returns are not a problem that keeps waiting patiently — they expire.

10What goes in each table

• B2B — every invoice to a registered buyer, invoice by invoice, with their GSTIN
• B2C Large — inter-state supplies to unregistered buyers above the prescribed invoice value, reported invoice-wise
• B2C Small — all other supplies to unregistered buyers, reported as a consolidated summary by rate and place of supply
• Exports and SEZ supplies — with or without payment of tax, plus shipping bill details
• Credit and debit notes — separately for registered and unregistered recipients
• Advances received and adjusted
• HSN-wise summary of outward supplies — mandatory, and increasingly validated by the portal
• Documents issued — the serial ranges of invoices, credit notes and delivery challans

11Practical filing discipline

• Reconcile your sales register against GSTR-1 before filing, not after — once filed the buyer sees it
• File GSTR-1 before GSTR-3B for the period, so GSTR-1A stays available as a safety net
• Never skip a nil return; the ₹20 per day accrues on nothing at all
• Check the HSN summary rather than accepting the auto-populated figures blindly
• Watch the place of supply on inter-state B2C entries — this is the most common source of later notices
• If you are on QRMP, use the IFF for months one and two as a courtesy to your buyers, not as an afterthought
• Clear the oldest pending GSTR-3B first if Rule 59(6) has blocked you