GSTR-3B is the summary return that every GST-registered business files monthly or quarterly. Yeh self-declaration return hai jisme outward supplies + inward supplies + tax liability + ITC claim sab summarize kiya jata hai. Late filing = daily late fee + 18% interest + potential ITC disallowance.
Filing season FY 2025-26 critical numbers: - Monthly filers: 12 returns/year × ₹50K-5L annual late fee risk - QRMP filers: 4 quarterly returns + 8 PMT-06 monthly tax payments - ITC reconciliation: Mandatory monthly per Rule 36(4) - Average compliance cost: ₹3,000-15,000/month depending on transaction volume
Common pain points that this article solves: - Confused between Monthly vs QRMP scheme - GSTR-2B mismatch with purchase register - RCM transactions not reported correctly - Late fee calculation unclear - NIL return process complicated
Yeh article aapko complete framework deta hai — due dates, step-by-step portal filing, ITC reconciliation strategy, RCM handling, late fee structure, 8 common mistakes, aur ₹50K-5L annual savings through proper filing.
# GSTR-3B Basics
### What is GSTR-3B - Summary return for declaring tax liability + claiming ITC - Self-declaration basis (not invoice-level like GSTR-1) - Mandatory for all regular GST-registered businesses - Composition dealers file CMP-08 instead (not GSTR-3B) - Casual taxable persons file GSTR-3B if applicable
# Filing frequency options
| Scheme | Eligibility | Returns/year | Tax payment |
|---|---|---|---|
| Monthly | Mandatory if turnover > ₹5 crore prev FY | 12 GSTR-3B | Monthly with return |
| QRMP | Optional for turnover ≤ ₹5 crore prev FY | 4 GSTR-3B + 8 PMT-06 | Monthly via PMT-06 |
### Switching between schemes - Opt-in/opt-out window each quarter - Choice made at start of quarter - Cannot mid-quarter switch - Plan based on cash flow + transaction complexity
# Due Dates — FY 2025-26
### Monthly Filers 20th of next month for all states.
Example schedule:
| Tax period | Due date |
|---|---|
| April 2026 | 20 May 2026 |
| May 2026 | 20 June 2026 |
| June 2026 | 20 July 2026 |
| ... | ... |
| March 2026 | 20 April 2026 |
# QRMP Filers — State-wise Schedule
Category X states (22nd of month following quarter end): - Chhattisgarh, MP, Gujarat, Maharashtra, Karnataka, Goa, Kerala, Tamil Nadu, Telangana, Andhra Pradesh, Daman & Diu, Dadra & Nagar Haveli, Puducherry, Andaman & Nicobar, Lakshadweep
Category Y states (24th of month following quarter end): - All other states/UTs (J&K, Ladakh, Himachal, Punjab, Chandigarh, Uttarakhand, Haryana, Delhi, Rajasthan, UP, Bihar, Sikkim, Arunachal, Nagaland, Manipur, Mizoram, Tripura, Meghalaya, Assam, West Bengal, Jharkhand, Odisha)
# QRMP quarter schedule (FY 2025-26)
| Quarter | Tax period | Due date (Cat X / Cat Y) |
|---|---|---|
| Q1 | Apr-Jun 2026 | 22/24 July 2026 |
| Q2 | Jul-Sep 2026 | 22/24 October 2026 |
| Q3 | Oct-Dec 2026 | 22/24 January 2027 |
| Q4 | Jan-Mar 2026 | 22/24 April 2026 |
### PMT-06 monthly tax payment (QRMP) - Due: 25th of next month (for first 2 months of each quarter) - Last month: Tax paid via quarterly GSTR-3B - Two methods: - Self-assessment: Pay actual tax based on monthly liability - 35% method: Pay 35% of previous quarter's cash tax (fixed sum)
# GSTR-3B — Step by Step Filing
# Pre-filing preparation
Books reconciliation: - Total outward supplies (taxable, exempt, nil-rated, exports) - Total inward supplies (B2B, B2C, RCM) - ITC claimed for the period - Tax already paid (advance, RCM)
Documents needed: - Sales register - Purchase register - GSTR-2B (auto-populated from suppliers' GSTR-1) - Bank statements for cross-verification
# Table-by-table guide
# Table 3.1 — Outward Supplies & Inward Supplies Liable to RCM
| Sub-table | Description |
|---|---|
| 3.1(a) | Outward taxable supplies (other than zero-rated, nil-rated, exempt) |
| 3.1(b) | Outward taxable supplies (zero-rated) — exports, SEZ |
| 3.1(c) | Other outward supplies (nil-rated, exempt) |
| 3.1(d) | Inward supplies (liable to reverse charge) |
| 3.1(e) | Non-GST outward supplies (petrol, alcohol, etc.) |
Fill amounts + tax (IGST/CGST/SGST/Cess) per sub-table.
# Table 4 — Eligible ITC
| Sub-table | Description |
|---|---|
| 4(A)(1) | Import of goods |
| 4(A)(2) | Import of services |
| 4(A)(3) | Inward supplies liable to RCM (other than above) |
| 4(A)(4) | Inward supplies from ISD |
| 4(A)(5) | All other ITC (regular B2B purchases) |
| 4(B)(1) | ITC reversed — Rule 42/43 (proportionate for exempt supplies) |
| 4(B)(2) | Others (e.g., ITC on capital goods sold) |
| 4(C) | Net ITC available |
| 4(D)(1) | Ineligible ITC (Section 17(5)) |
| 4(D)(2) | Ineligible others |
# Table 5 — Exempt, Nil-rated, Non-GST Inward Supplies
| Sub-table | Description |
|---|---|
| 5(A) | From supplier under composition scheme |
| 5(B) | Exempt inward supplies |
| 5(C) | Nil-rated supplies |
| 5(D) | Non-GST supplies |
# Table 6 — Tax Payment
Auto-calculated based on liability (Table 3.1) minus ITC (Table 4) = Net cash tax payable.
Options: - Cash ledger payment (electronic cash ledger) - ITC adjustment (electronic credit ledger) - Manual entry of cash payment
# Table 6.1 — TDS/TCS Credit
If you received TDS/TCS credits (rare for regular taxpayers, common for e-commerce sellers).
# Submit + File
- Preview return summary
- Verify all amounts
- Click "File GSTR-3B"
- Authenticate via EVC (OTP) or DSC (digital signature)
- Acknowledgment number generated
- Tax payment auto-debited from electronic ledgers
# ITC Reconciliation with GSTR-2B
### Why GSTR-2B matters - Rule 36(4): ITC claim ONLY to GSTR-2B extent (no buffer) - Section 16(2)(aa): Supplier compliance is buyer's responsibility - Auto-population: GSTR-2B generated 14th of every month for previous month
# Reconciliation process
#### Step 1: Download GSTR-2B - GST portal → Returns Dashboard → GSTR-2B → Select month → Download - Excel/JSON format
#### Step 2: Compare with purchase register - Match invoice-by-invoice - Common categories: - Matched: Invoice in both = claim ITC - In GSTR-2B but not in purchase register: Verify with supplier, add if genuine - In purchase register but not in GSTR-2B: Supplier hasn't filed GSTR-1; ITC cannot be claimed yet - Amount mismatch: Resolve with supplier
#### Step 3: Communication with non-compliant suppliers - Send formal email to supplier - Mention specific invoice + amount - Request immediate GSTR-1 filing - Track follow-up
#### Step 4: Claim ITC strategy - Current month: Claim only matched ITC - Pending ITC (supplier not filed): Park in "ITC pending ledger" - Subsequent months: Claim once supplier files GSTR-1 - Time limit: ITC must be claimed by November 30 of following FY OR before filing annual return, whichever earlier
# Worked example
Scenario: ABC Pvt Ltd, monthly filer, May 2026
- Total ITC per purchase register: ₹2,50,000
- GSTR-2B reflected: ₹2,30,000
- Mismatch: ₹20,000 (3 invoices from non-compliant supplier)
Action: - Claim ITC in GSTR-3B May: ₹2,30,000 (GSTR-2B amount) - Reserve ₹20,000 in pending ledger - Follow up with supplier - When supplier files GSTR-1 + appears in GSTR-2B → claim ₹20,000 in subsequent month
If never resolved: ₹20,000 ITC permanently lost — cost to business + bad supplier relationship trigger.
# Reverse Charge Mechanism (RCM)
# Common RCM scenarios
| Service/Goods | RCM trigger |
|---|---|
| Goods Transport Agency (GTA) | Service to specified recipients |
| Legal services from advocate/firm | To business entity |
| Director's services | To company |
| Sponsorship received | From non-profit/government |
| Import of services | If from unregistered foreign supplier |
| Renting of motor vehicle for passenger transport | From non-corporate to corporate |
| Security services | From non-corporate to registered person |
# RCM tax + ITC flow
- Pay tax on RCM transactions in Table 3.1(d)
- Self-invoice generated under Section 31(3)(f)
- Claim ITC of same amount in Table 4(A)(3) — if otherwise eligible
- Net cash impact: Zero (for ITC-eligible business)
### Common RCM mistakes - Skipping declaration: AO scrutiny + interest + penalty - Wrong tax rate: Use applicable rate, not default 18% - No self-invoice: Section 31(3)(f) violation + ₹25,000 penalty - ITC not claimed: Recipient takes tax burden but loses ITC offset
# Late Fee + Interest Structure
# Late filing fee (Section 47)
| Return type | Late fee per day | Maximum cap |
|---|---|---|
| GSTR-3B with tax liability | ₹50 (₹25 CGST + ₹25 SGST) | ₹5,000 |
| NIL GSTR-3B | ₹20 (₹10 CGST + ₹10 SGST) | ₹500 |
### Late filing interest (Section 50) - 18% per annum on net cash tax payable - Calculated daily from due date to actual payment - ITC-adjusted portion NOT charged interest
# Worked example — 60 days late filing
Scenario: ₹1,00,000 net cash tax, 60 days late
Costs: - Late fee: ₹50 × 60 = ₹3,000 (within ₹5K cap) - Interest: ₹1,00,000 × 18% × 60/365 = ₹2,959 - Total: ₹5,959 extra cost
Plus: 6+ months consistent late filing = GST registration suspension risk under Rule 21A.
# NIL Return Filing — SMS Method
### Eligibility for SMS method - No outward supplies in tax period - No inward supplies with RCM - No ITC claim - No tax payment due
### SMS format
NIL 3B GSTIN MMYYYYExample: NIL 3B 27AAAAA0000A1Z1 052026
Send to: 14409
### Process
1. Send above SMS from registered mobile number
2. Receive 6-digit verification code SMS
3. Reply with: CNF 3B XXXXXX (confirmation code)
4. Receive Application Reference Number (ARN)
5. Done — filing complete in 2 minutes
### Limitations - Only for true NIL (no transactions at all) - Registered mobile number mandatory - Cannot revise NIL filing to non-NIL — must file proper return in next period
# Common GSTR-3B Mistakes
### Mistake #1: ITC over-claim beyond GSTR-2B
Issue: Auto-matching flags discrepancy; AO notice; interest 24% on excess; 100% penalty
Fix: Match GSTR-2B before claiming; if supplier not filed, defer ITC
### Mistake #2: Missing RCM declaration
Issue: RCM-applicable transactions not declared; auditor catches in scrutiny
Fix: Maintain RCM checklist; review every month before filing
### Mistake #3: Wrong tax-head allocation
Issue: Intra-state supply marked as inter-state (IGST instead of CGST+SGST)
Fix: Use Place of Supply rules correctly; system warnings catch most
### Mistake #4: Skipping Rule 42/43 reversal
Issue: Common ITC apportionment between taxable + exempt supplies missed
Fix: If exempt supplies present, mandatory ITC reversal calculation
### Mistake #5: Late filing accumulating fees
Issue: Daily ₹50 fee compounds; ₹5K cap reached + interest piles up
Fix: File on or before 20th even with payment dispute (pay later, file return)
### Mistake #6: Filing without payment
Issue: Return submitted but tax not credited; system treats as defaulted
Fix: Ensure cash ledger has sufficient balance OR ITC offsetting works
### Mistake #7: NIL filing skipped thinking "no business"
Issue: ₹20/day late fee accumulates; 6 months = ₹3,600 unnecessary cost
Fix: NIL return via SMS — 2 minutes monthly
### Mistake #8: Not tracking suppliers' filing
Issue: Suppliers not filing GSTR-1; ITC keeps deferring
Fix: Quarterly supplier audit; switch non-compliant ones
# Action Plan — Monthly GSTR-3B Routine
### Day 1-5 (next month) - [ ] Sales register finalization - [ ] Purchase register finalization - [ ] ITC claim shortlist preparation
### Day 6-13 - [ ] Bank reconciliation - [ ] RCM transactions identification - [ ] Tax calculation
### Day 14 - [ ] GSTR-2B downloaded (auto-generated) - [ ] Reconciliation with purchase register - [ ] Communication with non-compliant suppliers
### Day 15-18 - [ ] Resolve discrepancies - [ ] Adjustment entries - [ ] Tax payment via challan if needed
### Day 19-20 - [ ] Final review of GSTR-3B - [ ] File before 20th of month (monthly filers) - [ ] EVC/DSC authentication
### Year-end (Annual) - [ ] All 12 GSTR-3B reconciliation with books - [ ] GSTR-9 preparation (annual return) - [ ] Identify + reclaim any missed ITC before Nov 30
# References (verified 23 May 2026)
- GST Portal — Official GSTR-3B Filing
- ClearTax — GSTR-3B Filing Complete Guide
- TaxBuddy — QRMP Scheme vs Monthly Filing
- TaxGuru — GSTR-2B Reconciliation Rule 36(4)
- IndiaFilings — RCM under GST Complete Guide
- Bajaj Finserv — GSTR-3B Late Fee Interest Calculation
- CBIC — Notifications on GSTR-3B due dates
Disclaimer: Yeh article educational guidance hai based on CGST Act 2017 + IGST Act 2017 provisions for FY 2025-26. GSTR-3B due dates subject to CBIC notifications. State-wise QRMP categorization (X/Y) as per CBIC official list — verify current categorization. ITC rules under Rule 36(4) + Section 16(2)(aa) require careful application — invoice-level verification recommended for substantial ITC claims. RCM list may be amended by future GST Council notifications. Data verified 23 May 2026.
