How to Get GSTR-1 & GSTR-3B Monthly Filing in India
Navigating the Goods and Services Tax regime in India requires precision and a disciplined monthly cadence. The filing cycle involves submitting GSTR-1 for outward supplies and GSTR-3B to declare tax liability and pay dues, with a growing dependence on the Invoice Furnishing Facility (IFF) and auto-drafted GSTR-2B for reconciling eligible input tax credit. Missing deadlines can attract late fees and interest under the CGST Act, and repeated defaults can trigger a system-driven blocking of e-way bill generation, making timely compliance critical for uninterrupted business operations. This guide outlines a streamlined process tailored for Indian businesses in 2026, whether you are a first-time regular taxpayer, transitioning between monthly and QRMP (Quarterly Return Monthly Payment) schemes, or managing filings across multiple GSTINs. Our approach emphasizes accuracy over speed, ensuring your books, e-invoices, and returns stay reconciled so mismatches do not surface later as notices or blocked credit.
Before you start
- Active GSTIN registered on the official portal (gst.gov.in) with all authorized signatories mapped correctly
- Digital Signature Certificate (DSC) or EVC-enabled Aadhaar for authorized signatories to sign returns
- Access to accounting or billing software with updated ledgers, sales invoices, and purchase records for the tax period
- E-invoicing set up and functioning if your aggregate turnover crosses the applicable e-invoicing threshold
- Prior period GSTR-2B downloaded for input tax credit reconciliation against your purchase register
- Bank account linked for online payment via NEFT/RTGS, UPI, or net banking through the GST Portal
- HSN/SAC code list updated to the digit-level mandated for your turnover slab under current portal rules
- Reconciled outward supply data segregated by B2B, B2C, exports, and credit/debit notes for the period
Step-by-step
Step 1: Access the GST Portal & Verify Login Credentials
Log in to your registered account on gst.gov.in using your DSC or EVC-enabled Aadhaar. Confirm that all user roles — Authorized Signatory, Primary Authorized Signatory, and any additional users — have active, valid credentials before attempting any filing.
- Check that your registered mobile number and email are current, since OTPs for EVC filing route through these.
- If you manage multiple GSTINs, verify you are working in the correct entity before entering data.
Step 2: Reconcile Books with E-Invoice and E-Way Bill Data
Before entering anything in GSTR-1, cross-check your accounting ledger against e-invoice records (if applicable) and any e-way bills generated for the period. This early reconciliation catches duplicate entries, missed invoices, and value mismatches before they propagate into your return.
Any credit notes, debit notes, or invoice amendments from prior periods should also be identified now so they can be reported in the correct section of GSTR-1.
Step 3: File GSTR-1 for Outward Supplies (or IFF if on QRMP)
Navigate to the 'Returns Dashboard', select the correct tax period, and choose GSTR-1. Enter details of all outward supplies made during the period, segregated by B2B, B2C large, B2C small, exports, and nil-rated/exempt categories. Ensure HSN codes are entered at the mandated digit level for your turnover bracket.
If you have opted into the QRMP scheme, you will instead use the Invoice Furnishing Facility (IFF) for the first two months of the quarter and file the consolidated GSTR-1 in the third month.
Step 4: Download and Review GSTR-2B for Input Tax Credit
Once your suppliers file their returns, GSTR-2B is auto-generated on the portal as a static statement of eligible and ineligible input tax credit for the period. Download it and compare it line-by-line against your purchase register.
- Flag any invoices your suppliers have not uploaded — you may need to follow up with them before claiming that credit.
- Note any credit marked ineligible (e.g., blocked credit under Section 17(5)) so it is excluded from your GSTR-3B claim.
Step 5: Reconcile Input Tax Credit (ITC) Before Filing GSTR-3B
Before filing GSTR-3B, verify your ITC ledger against the credit reflected in GSTR-2B and the credit claimed in your books. Resolve mismatches between supplier-reported and recipient-claimed figures to prevent disallowance of credit during a later audit or scrutiny notice.
Where a supplier has short-filed or delayed their return, consider provisional treatment cautiously and follow up directly, since claiming credit not reflected in GSTR-2B can draw departmental queries.
Step 6: File GSTR-3B for Tax Liability
Proceed to file GSTR-3B, summarizing the tax payable on outward supplies for the period. Declare eligible ITC as reconciled in the previous step, apply any reversals required under the rules, and calculate net tax liability after setting off input credit against output tax in the prescribed order (IGST, then CGST/SGST).
Step 7: Generate Challan and Make Payment
Once liabilities are declared in GSTR-3B, generate the payment challan (Form GST PMT-06) through the portal. Pay the dues using NEFT/RTGS, UPI, or net banking before the due date to avoid interest accruing on the unpaid tax amount.
If you are on QRMP, remember the fixed-sum or self-assessment method applies for the first two months, with final reconciliation at quarter-end.
Step 8: Verify Filing Status and Save Acknowledgements
After successful submission and payment, download the Application Reference Number (ARN) and filed-return PDF for both GSTR-1/IFF and GSTR-3B. Save these records securely, along with the payment challan, as proof of timely compliance for at least the statutory retention period.
Step 9: Set Up a Recurring Compliance Calendar
Build a simple internal calendar marking your GSTR-1/IFF due date, GSTR-3B due date, and a mid-cycle reconciliation checkpoint each month. A recurring reminder a few days before each deadline gives you buffer time to resolve portal errors, OTP issues, or last-minute data corrections without risking a late filing.
Common mistakes to avoid
- Filing GSTR-3B without reconciling ITC against GSTR-2B first, which risks credit disallowance later
- Submitting returns close to the deadline and getting caught by portal slowdowns or OTP delivery delays
- Using outdated HSN codes or the wrong digit-level requirement for your turnover bracket in GSTR-1
- Ignoring credit notes or amendments from earlier periods until they pile up and cause reconciliation headaches
- Claiming ITC on invoices not reflected in GSTR-2B without first confirming the supplier has actually filed
- Mixing up QRMP-scheme obligations (IFF vs. quarterly GSTR-1) and missing an interim filing window
- Failing to reverse ineligible or blocked credit under Section 17(5), leading to understated tax liability
- Not retaining ARN and challan records systematically, which slows down responses to later departmental notices
Frequently asked questions
What is the due date for monthly GST filing?
GSTR-3B is generally due by the 20th of the following month for most regular taxpayers, though staggered due dates (22nd or 24th) can apply based on the state of principal place of business. GSTR-1 is typically due by the 11th of the following month for monthly filers. Always confirm the exact date on the GST Portal for your category, since due dates are occasionally extended by notification.
Can I file monthly returns if my business is small?
Yes. Small taxpayers below the prescribed aggregate turnover threshold may opt into the QRMP scheme and file quarterly GSTR-1 (using IFF for interim months) with monthly tax payments, or they can choose to remain on monthly filing if they prefer. The choice is exercised on the portal at the start of the relevant period.
What happens if I miss the GSTR-1 or GSTR-3B deadline?
Late fees accrue per day of delay, and interest is charged on any unpaid tax from the original due date. Late fee amounts and caps have changed over recent years and vary by return type and taxpayer category, so confirm the current late fee and interest rate schedule on the GST Portal or with your tax advisor rather than relying on a fixed figure.
How do I correct errors in a filed GSTR-1?
Once GSTR-1 is filed, you generally cannot edit that period's return directly. Corrections are made in a subsequent period's GSTR-1 through the amendment tables (for invoices, credit/debit notes, or B2C-to-B2B reclassification). Keep a clear internal note of what was corrected and when, since amendment history matters if a query arises later.
Is GSTR-1 mandatory for all taxpayers?
Regular taxpayers must file GSTR-1 (or use IFF under QRMP), even if there were no outward supplies during the period, in which case a Nil return is filed. Composition scheme dealers file a different, simplified return instead of GSTR-1 and GSTR-3B.
What is GSTR-2B and why does it matter for filing?
GSTR-2B is a static, auto-generated statement showing input tax credit available to you based on what your suppliers have reported in their returns for the period. It has become the primary reference for how much ITC you can safely claim in GSTR-3B, so reconciling your purchase register against it each month is a core step, not an optional check.
Can I file GSTR-3B before GSTR-1 for the same period?
The portal generally expects GSTR-1 (or IFF) to be filed before GSTR-3B for the corresponding period, since GSTR-3B liability figures are meant to align with the outward supply data already reported. Attempting to file out of sequence typically triggers a portal validation error.
What if my supplier hasn't filed their return and my ITC doesn't show in GSTR-2B?
If a supplier invoice isn't reflected in your GSTR-2B, the safest approach is to follow up with the supplier to file promptly rather than claiming the credit provisionally. Departmental scrutiny increasingly cross-checks claimed ITC against GSTR-2B, and mismatches are a common trigger for notices.
Do I need a professional to file monthly GST returns, or can I do it myself?
Businesses with simple, low-volume transactions sometimes self-file using accounting software integrated with the GST Portal. However, once you have multiple GSTINs, e-invoicing, ITC reversals, or export transactions, engaging a qualified GST practitioner materially reduces the risk of reconciliation errors and missed reversals.
What records should I retain after filing?
Retain the filed return PDF, ARN acknowledgement, payment challan, GSTR-2B download for the period, and your reconciliation working papers. Statutory retention requirements under GST law generally run several years from the due date of the annual return, so archive these systematically rather than only for the current filing cycle.
How does switching between QRMP and monthly filing work?
Taxpayers eligible for QRMP can opt in or out of the scheme during specified windows on the GST Portal, generally ahead of the start of a quarter. Once opted in, you use IFF for interim-month invoice reporting and file the consolidated GSTR-1 and GSTR-3B for the quarter; switching back to monthly filing follows a similar portal-driven option window.
Does e-way bill generation get blocked for GST non-compliance?
Yes, the GST system can restrict e-way bill generation for GSTINs that have failed to file GSTR-3B for a specified consecutive number of return periods. Staying current on filings avoids this operational disruption, which can directly hold up goods movement and logistics.
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