How to File GST Returns: Complete Process

GST return filing is the monthly and annual compliance obligation for every registered taxpayer in India. Each return captures a different slice of your business activity — outward supplies, input tax credit, tax payment, reverse charge, and annual reconciliation — and together they form the complete picture the GST department uses to verify your tax position. Getting any one of them wrong, late, or missed can trigger late fees, interest charges, GSTIN suspension, and in extreme cases prosecution. This pillar guide covers every return you’ll touch, the due dates you must hit, the late fee and penalty schedule, and the workflow FinTax24 uses for our 12,000+ monthly filings.

The Five Returns Every Regular Taxpayer Files

The GST regime has a layered return system, with each return serving a specific compliance purpose.

GSTR-1 — Outward Supplies Return

GSTR-1 captures every tax invoice, credit note, debit note, advance receipt, and export invoice issued during the month. B2B invoices are reported in Table 4 with the buyer’s GSTIN (so the buyer can claim ITC); B2C invoices in Table 5 by state and rate. Exports go in Table 6A with Letter of Undertaking (LUT) details. The monthly due date is the 11th of the following month (13th for QRMP filers). GSTR-1 data auto-populates into the buyer’s GSTR-2B, so errors here directly impact your customers’ ability to claim ITC — disputes and withheld payments are common consequences.

GSTR-3B — Summary Self-Assessed Return

GSTR-3B is the only return that triggers actual tax payment. It is a six-table summary: Table 3.1 captures outward tax liability, Table 4 the ITC claim (auto- populated from GSTR-2B), Table 5 the ITC reversals (e.g., for non-payment to supplier after 180 days, blocked credits), Table 6 ineligible ITC, and Table 7 interest and late fees. Net tax = Table 3.1 minus Table 4. Due date is the 20th of the following month (22nd-24th for QRMP).

GSTR-2A and GSTR-2B — ITC Statements

These are not returns you file — they are auto-generated statements available on the GST portal. GSTR-2A is a dynamic read-only view that updates as your suppliers file GSTR-1. GSTR-2B is a static statement generated at month-end, locking in the eligible ITC for that month. You use GSTR-2B to claim ITC in GSTR-3B. Any invoice in your purchase register but missing from GSTR-2B indicates a supplier who has not filed GSTR-1 — your ITC is at risk unless they file and you re-import.

GSTR-9 — Annual Return

Filed by 31 December of the following financial year, GSTR-9 consolidates all monthly/quarterly GSTR-1 and GSTR-3B filings into a single annual reconciliation with 19 tables covering outward supplies, ITC claimed and reversed, tax paid, refunds, transactions with composition dealers, and differences vs. books of accounts. Mandatory for every regular taxpayer.

GSTR-9C — Reconciliation Statement

A separate reconciliation statement comparing GST returns with audited financial statements. Required for taxpayers with aggregate turnover above ₹2 crore in the financial year. Self-certified by the taxpayer, additionally certified by a chartered accountant or cost accountant. Due by 31 December.

The Two Returns Composition Dealers File

Composition taxpayers have a simplified annual structure:

CMP-08 — Quarterly Statement-cum-Payment

Filed by the 18th of the month following each quarter (e.g., CMP-08 for Apr-Jun is due by 18 July). Captures the summary of outward supplies, tax payable at composition rate, and tax payment. No ITC claim is possible under the composition scheme.

CMP-02 — Annual Return

Filed by 30 April of the following financial year. A consolidated annual return with quarterly summary and annual reconciliation.

QRMP Scheme — Quarterly Return Monthly Payment

The QRMP scheme is available for small taxpayers with aggregate turnover up to ₹5 crore. It splits the return-filing burden while keeping tax payment monthly.

• GSTR-1 is filed quarterly by the 13th of the month after the quarter ends (e.g., Q1 Apr-Jun GSTR-1 due by 13 July).

• GSTR-3B is filed monthly by the 22nd-24th with payment only (no return data, just tax payment via PMT-06 challan).

• First two months of the quarter are “no tax due” by default — but if the business has tax liability in those months, the GSTR-3B must be filed with payment.

QRMP suits businesses with low monthly volatility and an established supplier base. For fast-growing businesses or those with significant inter-state operations, monthly GSTR-1 is preferable for ITC chain visibility.

GSTR-1 Step-by-Step Filing Process

1. Data collection — By the 1st of the month, gather all sales invoices issued in the previous month, plus credit notes, debit notes, advances, and exports. Reconcile with your accounting system (Tally, Zoho Books, QuickBooks).

2. B2B invoice preparation — For each B2B invoice, record the buyer’s GSTIN, invoice number, date, taxable value, and tax rate. Verify HSN/SAC code is correct. For inter-state invoices, ensure IGST (not CGST+SGST) is applied.

3. B2C invoice preparation — Group B2C invoices by state and tax rate. POS place of supply is the customer’s state. For e-commerce sales, record the marketplace’s GSTIN as the supplier and your GSTIN as the seller.

4. HSN summary — Generate the HSN-wise summary showing total quantity, value, and tax for each HSN code. B2B aggregate turnover above ₹5 crore requires 6-digit HSN; below that, 4-digit is sufficient.

5. Login and file — On gst.gov.in, go to Returns → Returns Dashboard. Select the financial year and month. Choose GSTR-1. Upload the JSON file (if using offline tool) or enter directly. Submit using EVC (6-digit OTP to authorised signatory’s mobile) for proprietorships, or DSC for companies.

6. Verify ARN — The portal generates an Application Reference Number (ARN). Save it. GSTR-1 data now auto-populates into your buyers’ GSTR-2B.

GSTR-3B Step-by-Step Filing Process

1. Login to portal — On gst.gov.in, go to Returns Dashboard and select the financial year and month. Choose GSTR-3B.

2. Review Table 3.1 (outward supplies) — Auto-populated from GSTR-1. Verify the values match your books. If you filed a revised GSTR-1 earlier, this updates accordingly.

3. Review Table 4 (ITC claim) — Auto-populated from GSTR-2B. Verify the supplier invoices you expect to claim are present. For any missing invoices, follow up with the supplier before proceeding.

4. Review Table 5 (ITC reversal) — Identify ITC that must be reversed: blocked credits (motor vehicles, food, club memberships), non-business use, 180-day non-payment to supplier, etc. Enter reversal amounts.

5. Calculate net tax — Tax payable = Table 3.1 minus Table 4 plus Table 5 (reversal increases liability) plus Table 6 (ineligible ITC increases liability). The portal computes this.

6. Generate PMT-06 challan — If net tax is positive, the portal generates a payment challan. Pay via net banking, NEFT/RTGS, or over-the- counter at authorised banks. The challan is auto-reconciled with the return.

7. Submit and file — After successful payment, the return is auto-submitted. ARN is generated. Save it. The first GSTR-3B is critical — late filing blocks the GSTIN.

Input Tax Credit: How It Works and Common Mistakes

ITC is the cornerstone of GST — it removes the cascading effect of taxes by allowing businesses to offset GST paid on inputs against GST collected on outputs. But ITC is heavily rule-bound. The most common mistake is claiming ITC on blocked categories under Section 17(5) of the CGST Act:

• Motor vehicles — generally blocked, with exceptions for transport of goods, driving schools, and vehicles purchased for further sale

• Food and beverages, outdoor catering — blocked, with exceptions for inward supply used for furtherance of business (e.g., complimentary meals for employees)

• Membership of clubs, health clubs, fitness centres — fully blocked

• Rent-a-cab, life insurance, health insurance — blocked for employees, with exceptions for notified services

• Personal consumption — fully blocked

• Goods lost, stolen, or gifted — fully blocked

The second most common mistake is failing to reverse ITC when payment to the supplier is delayed beyond 180 days. Section 16(2)(a) requires ITC reversal if payment is not made within 180 days from the invoice date, with interest applicable on the reversed amount. The reversed ITC can be reclaimed once payment is made.

The third common mistake is mismatching the tax rate. If the seller charges 18% in GSTR-1 but the buyer’s GSTR-3B claims at 12%, the buyer must reverse the excess and re-claim at the correct rate. This is automated for most invoices but requires manual intervention for ambiguous HSN codes.

Reverse Charge Mechanism (RCM) in Returns

Under the Reverse Charge Mechanism, the recipient of certain supplies is liable to pay GST instead of the supplier. RCM applies to:

• Services received from unregistered persons (advocates, consultants, freelancers in some categories)
• Goods Transport Agency (GTA) services
• Legal services from advocates
• Services from directors where consideration exceeds ₹50,000 per month
• Renting of motor vehicles from unregistered persons
• Specified goods: used vehicles, leftover stone, tobacco leaves
• Services from any person via an e-commerce operator (where the operator is liable for TCS)

The recipient must self-invoice on the date of payment or service completion, report under RCM in GSTR-3B Table 3.1(d), and pay tax in cash (not from ITC). ITC on the corresponding purchase is available in the same month, but only to the extent of tax paid in cash. FinTax24 maintains an RCM register for every client and integrates it into monthly GSTR-3B preparation.

Due Date Master Calendar

Return	Taxpayer	Due Date	Frequency
GSTR-1	Regular, monthly	11th of following month	Monthly
GSTR-1	QRMP, quarterly	13th of month after quarter end	Quarterly
GSTR-3B	Regular, monthly	20th of following month	Monthly
GSTR-3B	QRMP, monthly	22nd (turnover up to ₹5 cr) or 24th (others)	Monthly
GSTR-3B	SEZ units, special	20th (or 24th for QRMP)	Monthly
CMP-08	Composition	18th of month after quarter end	Quarterly
GSTR-5	Non-resident	20th of following month	Monthly
GSTR-6	ISD	13th of following month	Monthly
GSTR-7	TDS deductor	10th of following month	Monthly
GSTR-8	TCS collector	10th of following month	Monthly
GSTR-9	All regular	31 December of following FY	Annual
GSTR-9C	Turnover > ₹2 cr	31 December of following FY	Annual
CMP-02	Composition	30 April of following FY	Annual

Late Fee, Interest, and Penalty Schedule

Missing a return or paying late triggers a graduated penalty structure:

Late Fee for GSTR-1 / GSTR-3B / CMP-08

• Turnover above ₹5 crore: ₹50/day (₹25 CGST + ₹25 SGST)
• Others: ₹25/day (₹12.50 CGST + ₹12.50 SGST)
• Nil return: ₹20/day (₹10 CGST + ₹10 SGST)
• Capped at ₹10,000 per return (₹5,000 for nil returns)

Late Fee for GSTR-9 / GSTR-9C

• Turnover above ₹5 crore: ₹200/day (₹100 CGST + ₹100 SGST), capped at 0.04% of turnover (max ₹25,000)
• Others: ₹100/day, capped at 0.04% of turnover (max ₹10,000)
• Nil return: no late fee

Interest on Late Tax Payment

18% per annum on the unpaid tax amount, calculated from the day after the due date to the actual payment date. Interest applies separately to CGST, SGST, and IGST.

Other Penalties

• Section 122: ₹10,000 or 10% of tax due (whichever is higher) for non-compliance
• Section 132: imprisonment 6 months to 5 years for deliberate tax evasion, plus fine
• Section 29: GSTIN cancellation for continued non-filing (no returns for 6 consecutive months)

E-Invoicing Mandate

E-invoicing is mandatory for B2B invoices from businesses with aggregate turnover exceeding ₹5 crore in any preceding financial year (Notification 13/2020). The invoice is generated via the government’s Invoice Registration Portal (IRP), which assigns a unique Invoice Reference Number (IRN) and QR code. E-invoicing auto-populates GSTR-1 Part A, eliminating manual entry. The threshold has been progressively reduced: ₹500 crore (FY 2020-21) → ₹100 crore (FY 2021-22) → ₹10 crore (FY 2022-23) → ₹5 crore (FY 2023-24). The next reduction to ₹1 crore has been notified but not yet implemented.

E-Way Bill Requirements

E-way bills are required for the movement of goods valued above ₹50,000 (with exceptions for some goods and intra-state handicraft movement). Generated on ewaybillgst.gov.in, the e-way bill contains the supplier’s and recipient’s GSTIN, invoice number, HSN code, value, and transport details. Validity depends on distance: 100 km for 1 day (extended for longer distances). Non-generation or expired e-way bills attract a penalty of ₹10,000 or the tax amount, whichever is higher, on the goods in transit.

Common Filing Errors and How to Avoid Them

Based on FinTax24’s review of 12,000+ monthly returns, the top errors that trigger notices or ITC loss are:

1. Wrong HSN code — using 4-digit HSN when 6-digit is required, or vice versa. Always verify the HSN based on your turnover bracket.

2. Tax rate mismatch — applying 18% when 12% is correct, or missing the IGST vs CGST+SGST distinction. This is the most common cause of GST department notices.

3. Inter-state vs intrastate confusion — classifying a supply as intrastate when the buyer is in a different state. This causes IGST notices and may require retrospective amendment of months of returns.

4. ITC claimed on blocked items — common with motor vehicles, food and beverages, and club memberships. Section 17(5) blocks these.

5. Credit note timing — issuing credit notes in a different period than the original invoice, causing GSTR-1 mismatch. Always issue credit notes in the same period or in a revision.

6. Advance receipt treatment — failing to declare advances received against future supply, which are taxable at receipt under Section 12 (time of supply for goods on advance).

How FinTax24 Handles Your Monthly Returns

Our monthly process is structured for zero-error filing:

1. Day 1-3 — Data extraction. We pull data from your accounting system (Tally, Zoho Books, QuickBooks, Busy) via API or scheduled export. Manual entries are collated.

2. Day 4-7 — Reconciliation. We compare your purchase register with GSTR-2B, identify missing supplier invoices, and email non-compliant suppliers to file their GSTR-1.

3. Day 8-10 — GSTR-1 preparation. We validate HSN codes, tax rates, inter-state/intrastate classification, and credit note timing before filing.

4. Day 11 — GSTR-1 filed. ARN recorded.

5. Day 12-18 — GSTR-3B preparation. We compute net tax liability, apply eligible ITC, identify reversals, and prepare the PMT-06 challan.

6. Day 19-20 — GSTR-3B filed. Payment made. ARN recorded.

7. Day 21-30 — Post-filing review. We respond to any officer queries, manage refund claims if applicable, and update your records.

We file 12,000+ returns per year with a 100% zero-penalty record. The same discipline applies whether your turnover is ₹20 lakh or ₹20 crore.

When this guide applies

Use this guide when you need a practical, plain-English explanation of the topic for an Indian business or taxpayer. We assume you already know the basics of Indian taxation and compliance — this guide focuses on the specific situations, deadlines, and pitfalls that matter in real filings.

Step-by-step process

1. Confirm the trigger event — turnover threshold, registration requirement, or compliance deadline that brings this topic into scope for your business.
2. Gather the documents you need (PAN, Aadhaar, GSTIN, bank statements, or the specific records called out in the linked forms).
3. File or register through the official portal (income tax e-filing, MCA, GST, FSSAI, or the relevant regulator). Keep acknowledgement numbers.
4. Pay any fee or tax due. Note the challan reference for your records.
5. Track the SLA — most approvals arrive in 3-30 working days; escalate through the regulator’s grievance portal if delayed.

Common pitfalls

• Filing after the due date without paying the late fee — penalty compounds per month under Section 234F for ITR, per return period for GST.
• Using the wrong ITR form or business code — leads to defective return notice under Section 139(9) and a fresh round of filing.
• Ignoring state-specific requirements (professional tax, shop & establishment, state GST registration) when operating across multiple states.

When to escalate

Talk to an expert if the situation involves cross-border transactions, notice from the department, or disputed turnover. Self-filing works for the routine cases but escalates quickly once a notice arrives.

Next steps

For a personalised check, use our eligibility wizards and free code search tools. To file end-to-end, see the linked service pages on FinTax24.