GST Filing Online 2025-26 – GSTR-1, GSTR-3B & GSTR-9 Complete Guide
Everything you need to know about GST return filing for FY 2025-26. Due dates, GST registration thresholds, ITC reconciliation, composition scheme, penalties for late filing, and step-by-step process explained by CA experts.
In This Guide – GST Filing FY 2025-26
- GST Registration – Who Must Register?
- All GST Returns Explained – GSTR-1, 3B, 9, 9C
- GST Return Due Dates & Late Fee Calendar
- Input Tax Credit (ITC) – How to Claim Correctly
- Composition Scheme – Small Business GST Option
- GST Rate Structure – 0%, 5%, 12%, 18%, 28%
- Step-by-Step GST Return Filing Process
- Penalties for Late & Non-Filing
- GST Notices – Types & How to Respond
- Common GST Mistakes to Avoid
- Frequently Asked Questions
GST Registration – Who Must Register & When?
GST registration is mandatory for businesses crossing the turnover threshold – and for some categories regardless of turnover. Operating without registration when required attracts heavy penalties.
Mandatory Registration – Turnover Threshold
Mandatory Registration – Regardless of Turnover
- Inter-state suppliers of goods or services
- E-commerce operators (Amazon, Flipkart sellers)
- Persons required to pay under Reverse Charge Mechanism (RCM)
- Input Service Distributors (ISD)
- Casual taxable persons (non-regular suppliers)
- Non-resident taxable persons making taxable supplies
- Persons supplying through e-commerce (notified categories)
Documents Required for GST Registration
Proprietorship / Individual
- PAN Card of proprietor
- Aadhaar Card (for verification)
- Photograph (JPG, max 100KB)
- Bank account proof (cancelled cheque / passbook)
- Business address proof (electricity bill / rent agreement)
Company / LLP
- PAN of Company / LLP
- Certificate of Incorporation
- MOA / AOA or LLP Agreement
- PAN & Aadhaar of all Directors / Partners
- Board Resolution for authorised signatory
Business Place of Supply
- Own premises – latest electricity / water bill
- Rented premises – rent agreement + NOC from owner
- Consent letter from property owner (if shared space)
- Municipal khata copy / property tax receipt
Businesses below the threshold can register voluntarily to claim Input Tax Credit on purchases, appear professional to large corporate clients who prefer GST-registered vendors, and to enable inter-state supply without restriction. Once registered voluntarily, you must comply with all GST filing obligations.
All GST Returns Explained – Which One Do You Need to File?
Not all GST-registered businesses need to file every return. Your return type depends on your turnover, business type, and GST scheme opted for.
| Return | Purpose | Who Files | Frequency | Due Date |
|---|---|---|---|---|
| GSTR-1 | Outward supplies (sales invoice details) | All regular taxpayers | Monthly or Quarterly (QRMP) | 11th (monthly) / 13th (quarterly) |
| GSTR-3B | Summary return + GST payment (ITC claim + tax liability) | All regular taxpayers | Monthly or Quarterly (QRMP) | 20th (monthly) / 22nd-24th (quarterly) |
| GSTR-2B | Auto-generated ITC statement from suppliers’ GSTR-1 | All regular taxpayers (auto-generated – no filing) | Monthly (auto) | Generated 14th – verify before 3B |
| GSTR-4 | Annual return for Composition Scheme dealers | Composition Scheme taxpayers only | Annual | 30 April |
| GSTR-9 | Annual return – reconciliation of full year’s GSTR-1 and GSTR-3B | All regular taxpayers (turnover > ₹2 crore mandatory) | Annual | 31 December 2026 |
| GSTR-9C | Reconciliation statement (audited) + CA/CMA certification | Taxpayers with turnover > ₹5 crore | Annual | 31 December 2026 |
| GSTR-7 | TDS deducted under GST by government departments and notified entities | GST TDS deductors only | Monthly | 10th of next month |
Taxpayers with annual turnover up to ₹5 crore can opt for the QRMP (Quarterly Return Monthly Payment) scheme. Under QRMP, GSTR-1 and GSTR-3B are filed quarterly, but tax must be paid monthly via a challan (PMT-06) by the 25th of each month. This reduces filing frequency from 24 returns/year to 8 returns/year while ensuring timely tax payment.
GST Return Due Dates & Late Fee Calendar FY 2025-26
Missing GST return deadlines attracts late fees and interest every single day. Here is the complete schedule for FY 2025-26.
Monthly Filers (Turnover > ₹5 Crore)
Annual & Quarterly Returns FY 2025-26
Input Tax Credit (ITC) – How to Claim Correctly
ITC is the backbone of GST. Claiming ITC incorrectly – or missing eligible ITC – is the most common cause of GST demand notices and excess tax payment.
How ITC Works – Simple Example
Your Purchase
You buy raw material worth ₹1,00,000 + GST 18%
Your Sale
You sell finished goods worth ₹1,60,000 + GST 18%
Net GST to Pay
₹28,800 collected – ₹18,000 ITC = Net payable
Conditions to Claim ITC
- You must have a valid tax invoice or debit note from supplier
- Goods or services must have been received
- Supplier must have filed GSTR-1 and credit appears in your GSTR-2B
- Tax must have been actually paid to the government by supplier
- You must have filed your GST returns for the period
- Goods/services are used for business (not personal use)
ITC NOT Available On
- Motor vehicles (except for specific business use)
- Food, outdoor catering, beauty treatment, health services
- Membership of a club, health and fitness centre
- Works contract services for construction of immovable property
- Goods or services for personal use
- ITC on goods destroyed, stolen, or gifted
From FY 2022-23 onwards, ITC can only be claimed to the extent it appears in your GSTR-2B. You cannot claim ITC based on physical invoices alone if the supplier has not filed their GSTR-1. Always reconcile your purchase register with GSTR-2B every month before filing GSTR-3B. Excess ITC claimed vs GSTR-2B results in automatic demand notices (DRC-01C).
GST Composition Scheme – Simplified GST for Small Businesses
The Composition Scheme allows eligible small businesses to pay GST at a flat rate on turnover – without collecting GST from customers or claiming ITC.
| Category | Turnover Limit | GST Rate | Return to File |
|---|---|---|---|
| Manufacturers (excluding notified goods) | Up to ₹1.5 Crore | 1% of Turnover | GSTR-4 (Annual) + CMP-08 (Quarterly) |
| Traders / Retailers | Up to ₹1.5 Crore | 1% of Turnover | GSTR-4 (Annual) + CMP-08 (Quarterly) |
| Restaurants (not serving alcohol) | Up to ₹1.5 Crore | 5% of Turnover | GSTR-4 (Annual) + CMP-08 (Quarterly) |
| Service Providers (CGST Notification 2/2019) | Up to ₹50 Lakh | 6% of Turnover | GSTR-4 (Annual) + CMP-08 (Quarterly) |
✅ Advantages of Composition Scheme
- Only 1 return per quarter (CMP-08) + 1 annual (GSTR-4)
- No need to maintain detailed purchase / sales records
- Very low tax rates (1% to 6%)
- Reduced compliance burden – suitable for small retailers
❌ Disadvantages / Restrictions
- Cannot collect GST from customers – tax is your own cost
- Cannot claim Input Tax Credit on purchases
- Cannot make inter-state supplies
- Not suitable if your customers are GST-registered businesses (they cannot get ITC from you)
GST Rate Structure – 0%, 5%, 12%, 18%, 28%
GST rates are divided into 5 slabs. Charging the wrong rate on invoices leads to demand notices, ITC reversal by customers, and penalties.
Exempt / Zero Rated
Essential food items (fresh fruits, vegetables, milk, eggs), healthcare services, educational services, exports, unbranded atta/rice/dal
Essential Goods
Branded food items, cooking oil, sugar, tea, coffee, domestic LPG, life-saving drugs, economy class air travel, rail tickets
Standard Goods
Processed food, computers, mobile phones, business class air travel, hotels (tariff ₹1000-₹7500/night)
Most Services
Most IT services, consulting, professional services, financial services, restaurants (AC), hotels (> ₹7,500/night), most manufactured goods
Luxury / Demerit
Automobiles, cement, luxury hotels, pan masala, tobacco, aerated drinks, large LCD TVs, casino / gambling + cess on top
Every product has an HSN (Harmonised System of Nomenclature) code and every service has a SAC (Services Accounting Code). The GST rate is linked to this code. Mentioning the wrong HSN/SAC on invoices results in the wrong rate being charged. Businesses with turnover above ₹5 crore must mandatorily mention 6-digit HSN codes on all invoices.
Step-by-Step GST Return Filing Process – GSTR-1 & GSTR-3B
File on the official gst.gov.in portal. GSTR-1 must be filed before GSTR-3B every month.
Prepare Invoice Data
Compile all sales invoices issued during the month. Categorise B2B (registered buyers), B2C (unregistered), exports, credit notes, and debit notes.
File GSTR-1 by 11th
Upload all outward supply invoices in GSTR-1. B2B invoices flow to your customer’s GSTR-2B automatically. File by the 11th.
Check GSTR-2B on 14th
Download GSTR-2B (auto-generated after 14th). Reconcile with your purchase register. Only claim ITC visible in GSTR-2B.
Prepare GSTR-3B
Fill outward supply summary, ITC claimed (from 2B), reverse charge liability, and net tax payable. Cross-verify with GSTR-1.
Pay GST by 20th
Pay net GST liability via online payment (Net banking / NEFT) using Electronic Cash Ledger. Utilise ITC from Electronic Credit Ledger first.
File GSTR-3B by 20th
Submit GSTR-3B after payment. File using DSC or EVC (OTP). Keep the ARN (Acknowledgement Reference Number) as proof of filing.
GSTR-1 before GSTR-3B – Always: Your GSTR-3B values must match your GSTR-1. Filing GSTR-3B with higher values than GSTR-1 creates a mismatch that triggers automated DRC-01A notices. Always file GSTR-1 first and verify totals before filing GSTR-3B.
Penalties for Late & Non-Filing of GST Returns
GST non-compliance penalties compound quickly. A single missed GSTR-3B can attract late fees of up to ₹10,000 plus 18% interest on unpaid tax.
Late Filing Fees
Serious Offences & Penalties
The government periodically introduces amnesty schemes with waived or reduced late fees for filing pending GST returns. If you have multiple unfiled returns, consult a CA immediately. Unfiled returns for 6 consecutive months trigger automatic GSTIN suspension under Rule 21A, and filing returns while suspended is not possible until suspension is lifted.
Common GST Notices – Types & How to Respond
GST notices are automated or officer-generated. Understanding the type helps you respond correctly within the time limit and avoid demand orders.
ITC Mismatch Notice
Issued when ITC claimed in GSTR-3B exceeds credit available in GSTR-2B. Automated notice from the GST portal.
Response: Pay the excess ITC with 18% interest OR reconcile and explain to officer within 30 days.
GSTR-1 vs GSTR-3B Mismatch
Issued when tax liability declared in GSTR-3B is lower than tax shown in GSTR-1 invoices.
Response: Pay the differential tax + interest, or file a detailed reply explaining the difference within 30 days.
Scrutiny Notice
Issued by GST officer after scrutiny of returns. Asks for explanation of discrepancies between filed returns and third-party data.
Response: File ASMT-11 with detailed explanation and supporting documents within 15-30 days.
Show Cause Notice (Pre-demand)
Issued before raising a demand order. Officer alleges short payment of tax or excess ITC claim. Most serious notice type.
Response: File DRC-06 with detailed reply and documents within the time given. Consult a CA immediately.
GSTIN Cancellation Notice
Issued when taxpayer has not filed returns for 6 consecutive months (regular) or 3 quarters (composition). GST officer proposes to cancel registration.
Response: File all pending returns immediately and submit REG-18 reply explaining compliance steps taken.
GST Audit Notice
Issued when your turnover crosses ₹2 crore or when the Commissioner directs a special audit. Requires submission of books and records.
Response: Submit all required documents, invoices, ledgers, and bank statements within stipulated time. CA assistance is strongly recommended.
Common GST Mistakes That Trigger Notices & Demands
These errors are the most frequent causes of GST notices, demand orders, ITC reversals, and penalties for businesses of all sizes.
Claiming ITC Without GSTR-2B Match
Claiming ITC based on physical invoices when the supplier has not filed their GSTR-1 is the most common GST error. Automated DRC-01A notices are issued for every mismatch between claimed ITC and GSTR-2B. Always cross-check GSTR-2B before filing GSTR-3B.
Wrong GSTIN on Invoices
Mentioning your own wrong GSTIN, state code error, or the buyer’s wrong GSTIN on invoices causes ITC rejection for the buyer and creates liability for you. Verify GSTIN before every invoice – the GST portal has a GSTIN search tool at gst.gov.in.
Not Filing NIL Returns
Even if there is zero business activity in a month, you must file a NIL GSTR-1 and NIL GSTR-3B. Missing NIL returns still attract late fees (₹20/day) and can eventually trigger GSTIN suspension. No business = still file returns.
Wrong GST Rate Applied
Charging 18% when the correct rate is 12%, or treating an exempt supply as taxable, leads to demand notices for excess collection and ITC reversal at buyer’s end. Always verify the HSN/SAC code and applicable rate before raising invoices.
Not Paying RCM Liability
Under Reverse Charge Mechanism (RCM), you (recipient) must pay GST directly to government on specified purchases (GTA services, legal services, unregistered vendors above threshold). Not paying RCM and not reporting it in GSTR-3B attracts 100% penalty plus interest on the unpaid amount.
Skipping GSTR-9 Annual Return
Many businesses with turnover above ₹2 crore skip GSTR-9 assuming it is optional. It is mandatory. Late fee is ₹200/day and can reach 0.25% of annual turnover. GSTR-9 also helps you identify and correct discrepancies between your monthly GSTR-1 and GSTR-3B filings before they become notice triggers.
FAQs – GST Filing FY 2025-26
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