GSTR-3B Filing — Due Dates, Tables and Step-by-Step Guide FY 2025-26

GSTR-3B Filing — Due Dates, Tables and Step-by-Step Guide FY 2025-26

Every regular GST taxpayer must file GSTR-3B — a summary return declaring outward supplies, input tax credit (ITC) and net tax payable — by the 20th of the following month (monthly filers) or the 22nd/24th after each quarter (QRMP filers). For FY 2026-27, GSTN has tightened auto-population from GSTR-2B and CBIC is cross-checking 3B figures against GSTR-1 in near real time. Filing the return accurately is no longer just a compliance checkbox; it directly protects your ITC chain and keeps your cash-ledger cost minimal.

What GSTR-3B Actually Is

GSTR-3B is a self-declared summary return under Rule 61 of the CGST Rules, 2017. You declare aggregate figures — not invoice-level data — across five major tables covering outward supplies, ITC and tax payment. It is not a replacement for GSTR-1 (which captures invoice details); it is a parallel, summary-level confirmation of your monthly GST position.

Think of it this way: GSTR-1 is your detailed transaction ledger; GSTR-3B is your monthly tax settlement statement. If they do not match, GSTN flags the discrepancy and the assessing officer follows up.

A few operational facts that practitioners often have to repeat:

• GSTR-3B must be filed even if there are no transactions for the month — a nil return.
• Once filed, GSTR-3B cannot be revised. Corrections to outward supply figures go through GSTR-1 amendments; ITC adjustments are handled in subsequent months' Table 4.
• From FY 2026-27, GSTN locks certain auto-populated fields in Table 4 (ITC). Manual overrides are logged and visible to the jurisdictional assessing officer in the comparison report.

Due Dates for GSTR-3B in FY 2026-27

The default statutory due date for monthly filers is the 20th of the following month. QRMP filers follow a staggered schedule tied to their state group.

Monthly Filers

> Important: CBIC occasionally extends due dates via notification — for natural disasters, technical outages or specific states. Always verify on the official unknown node before assuming an extension applies to you. Do not rely on informal WhatsApp forwards.

QRMP Filers

Under the QRMP (Quarterly Return Monthly Payment) scheme, taxpayers with aggregate turnover up to Rs. 5 crore in the preceding financial year may opt to file GSTR-3B quarterly while paying tax monthly via Form PMT-06 (by the 25th of months 1 and 2 of the quarter).

The quarterly GSTR-3B due date depends on your state group:

Group A states (22nd): Chhattisgarh, Madhya Pradesh, Gujarat, Maharashtra, Karnataka, Goa, Kerala, Tamil Nadu, Telangana, Andhra Pradesh, and the Union Territories of Daman & Diu, Dadra & Nagar Haveli, Puducherry, Andaman & Nicobar Islands and Lakshadweep.

Group B states (24th): Himachal Pradesh, Punjab, Uttarakhand, Haryana, Rajasthan, Uttar Pradesh, Bihar, Sikkim, all North-East states, West Bengal, Jharkhand, Odisha, Delhi, Jammu & Kashmir, Ladakh and Chandigarh.

Table-Wise Structure of GSTR-3B: What Goes Where

GSTR-3B has five main tables. Before you touch the portal, understand what each table captures and what a wrong entry costs you downstream.

Table 3.1 — Outward Supplies and Tax

This is your sales summary, broken into five rows:

• 3.1(a): Outward taxable supplies (other than zero-rated, nil-rated and exempt)
• 3.1(b): Outward taxable supplies — zero-rated (exports and SEZ supplies)
• 3.1(c): Other outward supplies — nil-rated and exempt
• 3.1(d): Inward supplies attracting reverse charge (RCM)
• 3.1(e): Non-GST outward supplies (e.g., alcohol, petroleum)

Figures here must reconcile exactly with the taxable value and tax you declared in GSTR-1 for the same period. Any mismatch triggers an auto-generated comparison report visible to the jurisdictional officer — no manual intervention needed on the department's side.

Table 3.2 — Inter-State Supplies

Table 3.2 captures inter-state supplies made to unregistered persons, composition taxpayers and UIN holders. It does not create new tax liability — that was already captured in Table 3.1 — but it drives IGST apportionment between states. If you make inter-state B2C sales and leave this blank, you will face reconciliation queries during the Annual Return (GSTR-9) review.

Table 4 — ITC Available, Reversed and Net

This is the most scrutinised table in GSTR-3B. From FY 2026-27, GSTN auto-populates Table 4 from GSTR-2B (the auto-drafted ITC statement generated on the 14th of each month). The structure is:

• 4(A): ITC available — sub-divided by import of goods, import of services, ISD credits, RCM and all other ITC (which ties to GSTR-2B)
• 4(B): ITC reversed — mandatory reversals under Rules 38, 42 and 43, plus the catch-all "others" row for Section 17(5) blocked credits
• 4(C): Net ITC available (4A minus 4B)
• 4(D): ITC reclaimed — previously reversed ITC that becomes re-eligible after Rule 42/43 true-up

If you claim ITC in 4(A) beyond what GSTR-2B shows for the period, the system logs it as a manual override. This single data point is one of the top triggers for DRC-01A scrutiny notices in FY 2026-27.

Table 5 — Exempt, Nil-Rated and Non-GST Inward Supplies

Report your total purchases that are exempt, nil-rated or non-GST here. This feeds the denominator in the Rule 42 calculation for ITC reversal on common inputs. Many taxpayers leave this table blank — and then wonder why their Rule 42 working does not reconcile.

Table 6.1 — Payment of Tax

This is where the liability settles. The system cascades your ITC in a defined sequence — IGST first against IGST liability, then IGST against CGST/SGST, then CGST against CGST, SGST against SGST — and the residual must be paid in cash via Form PMT-06 challan. Verify your electronic cash ledger balance before reaching this step.

Step-by-Step Filing Process on the GST Portal

Filing GSTR-3B correctly takes 30–45 minutes if your books are clean. Follow this exact sequence every month.

1. Log in at unknown node. Navigate to Returns > Returns Dashboard. Select the financial year and the tax period.

1. Open the GSTR-3B tile. The system auto-populates outward supply data from your filed GSTR-1 and ITC from GSTR-2B. Do not skip auto-population or override without a documented reason.

1. Verify Table 3.1 against your GSTR-1 for the same period. Check taxable value and IGST, CGST and SGST totals line by line. A Rs. 1 difference in tax will show up as a mismatch in GSTN's comparison report.

1. Review Table 4(A)(5) (all other ITC) against your GSTR-2B eligible ITC summary. Identify invoices in GSTR-2B relating to Section 17(5) blocked credits — catering, club memberships, personal car repairs, construction for immovable property — and move those amounts to Table 4(B) reversals.

1. Calculate your Rule 42 reversal if you make both taxable and exempt supplies with common input costs. Formula: ITC reversal = (Exempt outward turnover ÷ Total outward turnover) × Common ITC. Enter the result in Table 4(B)(1) or 4(B)(2) as applicable.

1. Check Table 5 — populate your exempt and nil-rated inward supplies so Rule 42 cross-referencing is clean in GSTR-9.

1. Confirm Table 6.1 (tax payment). Verify the ITC cascade is correct. Check your cash ledger balance in the portal. If it is insufficient, generate a PMT-06 challan under Services > Payments > Create Challan, complete payment via net banking or NEFT/RTGS, and wait for the credit to reflect before proceeding.

1. Preview the draft return using the "Preview" button. Download the PDF and do a final cross-check against your accounts receivable and accounts payable registers.

1. Validate and file. Proprietorships and individuals may use EVC (Electronic Verification Code via OTP). Companies and LLPs must use DSC (Digital Signature Certificate). If your DSC has expired, renew it before the due date — this is a common last-minute bottleneck.

1. Download and save the ARN (Acknowledgement Reference Number) and the filed return PDF. Archive these with the period's GSTR-1, GSTR-2B and your reconciliation workbook. You will need them for GSTR-9 and departmental audit.

ITC in GSTR-3B: What to Claim, What to Reverse

ITC is the most financially significant part of GSTR-3B — and the most audited. Three principles govern what you keep.

What You Can Claim

Claim ITC only for inward supplies that:

• Are reflected in your GSTR-2B for the period (or a prior period if the supplier filed late and you carried forward the claim)
• Relate to taxable business activities
• Are backed by a valid tax invoice, debit note or bill of entry
• Do not fall under the blocked-credit list in Section 17(5) of the CGST Act, 2017

Mandatory Reversals

Section 17(5) blocked credits must be reversed as soon as they appear in GSTR-2B. Common categories: motor vehicles for personal use, food and beverages, beauty treatments, club memberships, works contract services for immovable property (except factories or civil structures for plant), and goods or services for personal consumption.

Rule 42 — Mixed use of inputs and input services: Reverse the pro-rata exempt portion every month. Do a final true-up at year-end and adjust the difference in the first return of the next year.

Rule 43 — Capital goods used for mixed purposes: Reverse 1/60th of the eligible reversal amount each month over five years. Maintain a separate register of capital goods for this.

Rule 86B: If your taxable outward supplies in a month exceed Rs. 50 lakh, you must pay at least 1% of the tax liability in cash — ITC alone cannot discharge the full liability. Exceptions apply (exporters, government suppliers, taxpayers with clean compliance history as notified by CBIC). Check whether Rule 86B applies to you before zeroing out the cash column.

One Practical Pre-Filing Check

Before filing, compute: Net ITC claimed in Table 4(C) = GSTR-2B eligible ITC − Section 17(5) credits − Rule 42 reversal − Rule 43 reversal. If your 4(C) figure exceeds this calculation, stop and identify the variance before submitting.

Worked Example: The True Cost of a 52-Day Delay

Facts: A Pune-based manufacturer (monthly filer) misses the GSTR-3B due date for June 2026 (20th July 2026) and files on 10th September 2026 — 52 days late. His June 2026 tax position is:

Interest under Section 50(1) of the CGST Act runs at 18% per annum on the net cash component only — not on the tax offset by ITC.

Interest = Rs. 70,000 × 18% × 52 ÷ 365 = Rs. 1,797**

Late fee under Section 47 of the CGST Act (current notified rate: Rs. 50 per day split as Rs. 25 CGST + Rs. 25 SGST for tax-bearing returns, capped at Rs. 10,000):

Late fee = Rs. 50 × 52 = Rs. 2,600 (Rs. 1,300 CGST + Rs. 1,300 SGST)

Total cost of the 52-day delay = Rs. 1,797 + Rs. 2,600 = Rs. 4,397.

Scale this across four delayed returns in a year (average 40 days each) and the cumulative avoidable cost crosses Rs. 15,000 — before professional fees to respond to the DRC-01 notice that typically follows six months later.

For nil-return filers (no transactions in the month): late fee is Rs. 20 per day, capped at Rs. 500 per return. Even at Rs. 500 maximum exposure, the compounding reputational cost with the portal's compliance rating makes filing on time the obvious choice.

Three-Way Reconciliation: GSTR-1, GSTR-2B and GSTR-3B

GSTN's comparison engine reconciles your GSTR-3B against GSTR-1 and GSTR-2B automatically and makes the gaps visible to assessing officers. Run your own reconciliation first — three check-points, 30 minutes each month.

Outward-Supply Check

If GSTR-1 was not filed before GSTR-3B, auto-population is zero and you must manually enter figures — creating a permanent gap in GSTN's comparison report.

ITC Check

Compare GSTR-2B eligible ITC with Table 4(A)(5). Invoices from suppliers who have not yet filed their GSTR-1 will be absent from GSTR-2B. You cannot claim ITC for those invoices in the current period — wait until they appear in a future GSTR-2B, subject to the time limit under Section 16(4) of the CGST Act (no ITC after the 30th of November following the end of the financial year to which the invoice relates, or the date of filing the annual return, whichever is earlier).

Books-to-Return Check

Extract your outward supply register from your accounting software. Reconcile total taxable value and tax to GSTR-1. Extract your purchase register, filter for eligible ITC, and compare to GSTR-2B. Only then open the portal. A mismatch identified at this stage costs 15 minutes to fix; the same mismatch discovered during a departmental audit costs significantly more.

Common Mistakes That Trigger GST Notices

These errors appear consistently in practice. A pre-filing checklist eliminates almost all of them.

1. Claiming ITC above GSTR-2B. The portal logs every manual override. Any excess claim is visible to the assessing officer the day after you file and is a direct trigger for DRC-01A.

1. Not reversing Section 17(5) credits. If blocked-credit invoices appear in GSTR-2B and you claim them without reversing in Table 4(B), you face the original demand plus 24% interest (excess ITC claim rate under Section 50(3)) plus penalty.

1. RCM liability in the wrong table. Reverse charge inward supplies — legal and professional fees, GTA services, import of services, sponsorship — belong in Table 3.1(d), not 3.1(a). Filing in the wrong row distorts IGST/CGST/SGST allocation and causes cross-state settlement errors.

1. Blank Table 3.2 for inter-state B2C supplies. If you sell goods or services to unregistered buyers in another state, Table 3.2 must be filled. Leaving it blank causes IGST apportionment errors that surface — painfully — during GSTR-9 reconciliation.

1. Filing GSTR-3B before GSTR-1 is filed. From FY 2026-27, the system's auto-population depends on a filed GSTR-1. If you file 3B first with manually entered figures and GSTR-1 later, GSTN creates a permanent mismatch in the comparison report for that period.

1. Skipping the Rule 42 reversal. Businesses with any exempt or nil-rated outward supplies — and common input costs — must reverse proportionate ITC every month. This is not a year-end exercise; it is a monthly obligation under Rule 42(1).

1. PMT-06 timing error under QRMP. QRMP taxpayers who miss the 25th-of-month PMT-06 payment for months 1 or 2 of a quarter effectively defer tax. Interest under Section 50 runs from the original 20th due date of that month — not from the quarter's filing due date. The delay looks minor; the interest calculation can surprise you.

QRMP Scheme: How Your GSTR-3B Obligations Change

If your aggregate turnover in FY 2025-26 was up to Rs. 5 crore, you are eligible for QRMP. Your GSTR-3B obligations shift in three important ways.

• Filing frequency drops from 12 to 4 — one quarterly GSTR-3B per year. The due date is the 22nd or 24th of the month after the quarter closes, based on your state group.
• Monthly tax payment is still required via PMT-06 for months 1 and 2 of each quarter. You choose either the fixed-sum method (pay 35% of the net cash tax paid in the last filed quarterly return) or the self-assessment method (calculate actual liability for the month using GSTR-2B ITC). Whichever you choose, pay by the 25th.
• ITC accumulation risk: Since GSTR-2B is generated monthly but you file 3B quarterly, you must track ITC accumulation carefully across all three months. Suppliers who file GSTR-1 late may cause ITC to shift between months within the quarter — verify the total before you file the quarterly 3B.

Worked example: A Jaipur trader (Group B, due 24th) has Q1 FY 2026-27 aggregate quarterly tax of Rs. 1,20,000 — April Rs. 40,000, May Rs. 45,000, June Rs. 35,000 — all fully covered by ITC. She files on 24th July 2026 (due date). No PMT-06 payments were needed for April or May because self-assessed ITC exceeded liability each month. Result: zero late fee, zero interest.

If she files on 5th August instead — 12 days late — late fee = Rs. 50 × 12 = Rs. 600 (Rs. 300 CGST + Rs. 300 SGST). Small in absolute terms, but it also pushes her compliance rating down on the portal, which affects future refund processing speed.

Key Takeaways

• File GSTR-1 before GSTR-3B every period — the auto-population engine and GSTN comparison reports depend on a filed GSTR-1.
• Monthly filers: 20th of the following month. QRMP Group A states: 22nd; Group B states: 24th after quarter-end. Keep a calendar reminder — no system will file it for you.
• ITC must mirror GSTR-2B. Any claim above GSTR-2B is a manual override logged permanently on the portal. Never claim provisional ITC above GSTR-2B from FY 2026-27 onwards.
• Interest at 18% p.a. under Section 50(1) runs on net cash tax liability only — not on the gross tax before ITC offset. Calculate on the actual cash you owe, not the invoice total.
• Late fee: Rs. 50/day (capped at Rs. 10,000) for tax-bearing returns; Rs. 20/day (capped at Rs. 500) for nil returns. Even the nil-return cap at Rs. 500 is worth avoiding through timely filing.
• Run a three-way reconciliation (outward register → GSTR-1 → Table 3.1; purchase register → GSTR-2B → Table 4) before logging into the portal each month. Thirty minutes of prevention saves hours of correction.
• Section 17(5) reversals and Rule 42 calculations are mandatory monthly obligations, not year-end adjustments. Treating them as optional is the single fastest way to turn a clean return into a notice-triggering one.