GST Return Filing: GSTR-1 and GSTR-3B Due Dates and Steps

Quick answer: GST return filing for most regular taxpayers means GSTR-1 (sales) by the 11th and GSTR-3B (summary and payment) by the 20th of the following month. QRMP taxpayers with turnover up to Rs 5 crore file quarterly, by the 13th and the 22nd or 24th, and pay monthly. Late returns attract fees and 18% interest.

Every GST-registered business in India files returns, even in months with no sales. The system has become stricter since 2024: GSTR-3B now pulls liability from GSTR-1 and locks it, the Invoice Management System decides your input tax credit, and old returns face a three-year time bar. This guide explains which returns you file, the due dates, how GST return filing works step by step on the portal, late fees and interest with a worked example, the annual return, and the mistakes that cause notices.

Important: This is general information, not tax advice. Due dates are often extended and GSTN changes portal rules through advisories. Check the return calendar on the official GST portal and notifications on CBIC's GST site, or ask a chartered accountant.

Which GST returns do you need to file?

Return	What it covers	Who files	Due date
GSTR-1	Invoice-level details of outward supplies	Regular taxpayers	11th of next month (monthly) or 13th of month after quarter (QRMP)
IFF	B2B invoices for months 1 and 2 of a quarter	QRMP taxpayers, optional	1st to 13th of next month
GSTR-1A	Amendments to GSTR-1 for the same period	Optional, before GSTR-3B	After GSTR-1, before filing GSTR-3B
GSTR-3B	Summary of output tax, input tax credit and payment	Regular taxpayers	20th of next month (monthly) or 22nd/24th after quarter (QRMP)
PMT-06	Monthly tax payment	QRMP taxpayers	25th of next month for months 1 and 2
GSTR-9	Annual return	Regular taxpayers, subject to exemptions	31 December after the financial year
CMP-08 and GSTR-4	Quarterly payment and annual return	Composition taxpayers	18th after quarter; 30 April after year

Under QRMP, the GSTR-3B date depends on your state: the 22nd for one group of states and the 24th for the other. The portal shows your date on the return dashboard.

GSTR-1 vs GSTR-3B: how they fit together

GSTR-1 is what you tell the system you sold, invoice by invoice for B2B supplies and in summary for most B2C supplies. It flows to your buyers' IMS dashboard and GSTR-2B, so their input tax credit depends on your accuracy. Our explainer on the GST Invoice Management System shows the buyer's side.

GSTR-3B is where you settle up. Output tax is auto-populated from GSTR-1, input tax credit from your GSTR-2B, and you pay the difference in cash after using credit. From the July 2025 tax period, GSTN made the auto-populated liability in GSTR-3B non-editable, with further tables locked later in 2025. If your GSTR-1 was wrong, you fix it through GSTR-1A before filing GSTR-3B. Several articles in 2026 have reported that input tax credit in GSTR-3B would also be locked; at the time of writing we could not find a GSTN advisory confirming that, so check the portal's news section.

Monthly or quarterly: QRMP

If your aggregate turnover in the previous financial year was up to Rs 5 crore, you can opt for the Quarterly Return Monthly Payment scheme. You file GSTR-1 and GSTR-3B once a quarter but still pay tax monthly through PMT-06, either on a fixed-sum basis using 35% of last quarter's cash tax or on self-assessment. If your buyers want credit every month, upload their invoices through IFF in the first two months of the quarter.

Step-by-step GST return filing on the portal

Filing GSTR-1

1. Close your sales register. Make sure every invoice, credit note and debit note for the period is final and numbered in sequence.
2. Log in to the GST portal and open Returns Dashboard, choosing the financial year and period.
3. Enter or upload details. Add B2B invoices with the buyer's GSTIN, B2C large and small supplies, exports, credit and debit notes and amendments. Businesses using e-invoicing will see IRN invoices auto-populated.
4. Complete the HSN summary. Table 12 needs HSN or SAC codes chosen from the portal's list, split into B2B and B2C supplies, with the digit count set by your turnover. See our guide to HSN and SAC codes.
5. Complete the documents issued table (Table 13) with the serial number ranges you used.
6. Generate the summary, preview and file with DSC or EVC.

Filing GSTR-3B

1. Review IMS. Accept, reject or keep pending supplier invoices before GSTR-2B is generated on the 14th.
2. Check GSTR-2B against your purchase register, and recompute it if you change IMS actions.
3. Open GSTR-3B. Check the auto-populated liability against your GSTR-1; fix errors through GSTR-1A first.
4. Review input tax credit, reversing ineligible credit such as blocked items.
5. Offset liability. The portal applies credit and shows the cash payable.
6. Pay any cash due through a challan (PMT-06) by net banking, UPI or card where supported.
7. File with DSC or EVC and download the filed return.

Late fees and interest

Situation	Late fee per day (CGST + SGST)	Maximum per return
Nil GSTR-3B or nil GSTR-1	Rs 20 (10 + 10)	Rs 500
Other returns, turnover up to Rs 1.5 crore	Rs 50 (25 + 25)	Rs 2,000
Other returns, turnover Rs 1.5 crore to Rs 5 crore	Rs 50 (25 + 25)	Rs 5,000
Other returns, turnover above Rs 5 crore	Rs 50 (25 + 25)	Rs 10,000

These caps come from the 2021 late fee rationalization; inter-state supplies charge the equivalent under IGST. Interest at 18% a year applies on tax paid late in cash, calculated from the day after the due date to the date of payment. GSTR-9 has its own late fee rules linked to turnover. Late fees cannot be paid from input tax credit.

Worked example: monthly GSTR-3B filed 10 days late

Meera runs a design studio in Pune with turnover of Rs 1.2 crore and files monthly. In September she billed Rs 5,00,000 of services at 18%.

• Output tax: 5,00,000 x 18% = Rs 90,000 (CGST 45,000 + SGST 45,000)
• Eligible input tax credit in GSTR-2B: Rs 54,000
• Net cash payable: 90,000 - 54,000 = Rs 36,000

She files GSTR-3B on 30 October instead of 20 October, 10 days late.

• Late fee: Rs 50 x 10 days = Rs 500 (Rs 250 CGST + Rs 250 SGST), below her Rs 2,000 cap
• Interest: 36,000 x 18% x 10 / 365 = about Rs 178
• Total cost of the delay: about Rs 678, plus her buyers may question the delay

Small on its own, but repeated delays add up, and the GSTR-1 for October cannot be filed until GSTR-3B for September is done. You can check the tax arithmetic on any invoice with our sales tax calculator.

GST return filing for exporters and freelancers

Freelancers and agencies billing overseas clients still file GSTR-1 and GSTR-3B once registered, even though exports of services are zero-rated. Most export under a Letter of Undertaking (LUT), filed on the portal once each financial year, so no IGST is charged on the invoice. In GSTR-1, report these invoices in the exports table with the invoice number, date, value and port code or shipping bill details where relevant. In GSTR-3B, show the value as zero-rated outward supplies so it matches GSTR-1.

Keep the foreign inward remittance proof, such as a bank advice or FIRC, with each export invoice. Exports count toward aggregate turnover, so they affect your QRMP eligibility and the late fee cap that applies to you. If you have no domestic sales and few purchases, your monthly GST return filing will be short, but the dates and late fees still apply.

Annual return: GSTR-9 and GSTR-9C

GSTR-9 summarizes the year's supplies, credit and tax paid, and is due by 31 December after the financial year. Taxpayers with aggregate turnover up to Rs 2 crore have been exempted for recent years, and GSTR-9C (a self-certified reconciliation statement) applies above Rs 5 crore. Before filing, reconcile your books with the monthly returns and correct differences in the last return periods allowed for that year.

GST return filing checklist for each month

• All invoices issued and numbered; credit notes for returns raised (see our credit note guide)
• E-invoices registered on the IRP if you are above the limit (see e-invoice limit)
• E-way bill values match invoices for goods moved (see e-way bill guide)
• GSTR-1 filed with HSN summary and documents table
• IMS reviewed before the 14th; GSTR-2B reconciled
• GSTR-3B liability matches GSTR-1; corrections made in GSTR-1A
• Tax paid and GSTR-3B filed by the due date
• Filed returns and challans saved

Common mistakes

• Wrong buyer GSTIN in GSTR-1. The buyer loses credit and will chase you for an amendment.
• Using old rates. Many rates changed under GST 2.0 from 22 September 2025; see our guide to the new GST rates.
• Trying to fix GSTR-1 errors in GSTR-3B. Liability is locked; use GSTR-1A.
• Ignoring IMS. Deemed acceptance can pull wrong credit into GSTR-2B.
• Skipping nil returns. Late fees still apply, and non-filing risks cancellation.
• Leaving old returns pending. The three-year bar means they may become impossible to file.

Where your invoices fit

Accurate GST return filing starts with accurate invoices: correct GSTINs, HSN or SAC codes, rates and place of supply. Our GST invoice guide lists the mandatory fields, and new businesses should read about GST registration in India. If you are below the e-invoice limit, our free invoice generator creates a clean INR invoice as a PDF in your browser with one tax rate per invoice. It does not file GSTR-1 or GSTR-3B, connect to the GST portal, or generate IRNs or e-way bills, so keep your returns in the portal or your accounting software.