GST Tax File 2025 Made Easy: Step-by-Step GSTR-1 & GSTR-3B Guide for Businesses

GST (Goods and Services Tax) has become the basis of trade in India. As a businessman, filing your GST tax on time and accurately is not only a legal responsibility but also the key to maintaining the credibility and biggest advantage of your business—Input Tax Credit (ITC).

In the year 2025, with some changes in the GST rules, the process of filing GST returns online needs to be made even easier and flawless. If you are a small business, whether it is a proprietorship or a large company, this comprehensive guide will walk you through the entire process of filing GST tax, the required forms (such as GSTR-1 and GSTR-3B), and the things to keep in mind. Our aim is that you can easily complete this work yourself or with the help of your accountant, without any confusion or mistake.

Fundamentals of GST Filing: What are GSTR-1 and GSTR-3B?

Filing GST Tax primarily means filing two major return forms: GSTR-1 and GSTR-3B. Understanding both of these forms will solve half of your difficulty.

1. GSTR-1 Filing: Accounting for Your Sales

GSTR-1 is a monthly or quarterly return in which you have to give details of your 'Outward Supplies' i.e. all your sales.

What's included? Here are very invoice-wise details of what you have sold through GSTN-registered buyers (B2B), end consumers (B2C), exports, and credit/debit notes.

Significance: This return helps your buyers claim their Input Tax Credit (ITC). If you do not file GSTR-1 or give false information, your customers will not be able to claim ITC and this can damage your business relationships.

Due Date: 11th of the following month for monthly filers, and 13th of the following month after quarterly for quarterly filers under QRMP scheme.

2. GSTR-3B Filing: Tax Summary and Payment

GSTR-3B is a summary statement in which you have to give a summary of your total sales, total purchases (on which you have availed input tax credit in GST), and final tax liability. This is the form through which you make your final GST tax payment.

What's included?

Summary of sales of GSTR-1, auto-populated ITC from GSTR-2B, liability under Reverse Charge Mechanism (RCM), and payment of net tax.

Importance: It tells the government how much tax you have deposited in that period. Without filing GSTR-3B, you cannot even file GSTR-1.

Due Date: 20th of the following month for the monthly filer, and the 22nd or 24th of the next month (depending on the state) for the quarterly filer under the QRMP scheme.

How to File GST Tax Online: Step-by-Step Process

The GST online process is quite simple, provided you have all the data ready. Here' s a handy guide to GST portal filing:

Step 1: Prepare the necessary documents and data

Before filing GST tax, ensure that you have the following data and access available:

Valid GSTIN (GST Identification Number)

All tax invoices and credit/debit notes of sales and purchases.

GSTR-2B statement (This is the auto-generated ITC statement, which tells how much ITC you can claim).

Summary of sales with HSN/SAC code (HSN of 4 or 6 digits is mandatory depending on turnover).

You have a mobile number registered for DSC (Digital Signature Certificate) or EVC (Electronic Verification Code).

Step 2: Login and GSTR-1 filing on GST portal

Navigate: Go to Services → Returns → Returns Dashboard on the GST Portal

Select Period: Choose the financial year and return period.

GSTR-1 Prepare Online: Click on 'PREPARE ONLINE' in the GSTR-1 tile.

Enter Details: Fill in the invoice details in the various tables. For example, Table 4 for B2B sales, Table 7 for B2C (consumer) sales, and Table 12 for HSN Summary.

Submit and File: After filling in all the details, click on 'GENERATE SUMMARY', then 'SUBMIT'. Finally, click on the 'FILE GSTR-1' button and complete the filing using EVC (OTP) or DSC.

Step 3: GSTR-3B Filing: ITC Claim and Tax Payment Online

After filing GSTR-1, you will need to file GSTR-3B:

GSTR-3B Access: Go back to the Returns Dashboard and click on 'PREPARE ONLINE' in the GSTR-3B tile.

GSTR-2B Reconciliation: Before starting GSTR-3B, refer to GSTR-2B (Services > Returns > GSTR-2B). This is the final amount of input tax credit in GST you get on your purchase.

Fill Tax Liability (Table 3.1): Enter your total external supplies (summary of GSTR-1) and reverse charge liability here.

Claim ITC (Table 4): Here you will fill in the amount of input tax credit that matches GSTR-2B. Tip: The ITC claim should not always exceed GSTR-2B, otherwise the notice may come.

Offset Liability: Click on 'Make Payment/Post Credit to Ledger'. The system will automatically set off your tax liability using the ITC available in your credit ledger and the balance available in the cash ledger.

Challan Generation (if tax is due): If tax is still due in cash after set-off, click on 'CREATE CHALLAN', make GST tax payment online (Net Banking, NEFT, RTGS), and get the Challan Reference Number (CPIN).

Final Submission: On completion of the payment, click on 'PROCEED TO FILE' and file GSTR-3B using EVC or DSC.

Real-Life Example: Suppose Gaurav, a small businessman from Delhi, made sales of ₹1,00,000 in a month (including GST 18%) and paid 18% GST on a purchase of ₹20,000.

In GSTR-1: Details of sales of ₹1,00,000 filed.

In GSTR-3B: Showed an output tax liability (on sale) of ₹18,000 and claimed ITC (on purchase) of ₹3,600.

Net Tax Payable: ₹18,000 - ₹3,600 = ₹14,400. It has to be deposited as ₹14,400 GST Tax Payment.

Mandatory Returns and Important Due Date (2025)

Being an experienced businessman, you need to know that missing the GST return due date can result in a penalty (Late Fee).

GST Return Form an account Frequency General Due Date

GSTR-1 Details of Monthly/quarterly Monthly: 11th of next month

Sales/Outward Supplies

GSTR-3B Summary Returns and Tax Payments Monthly/quarterly Monthly: 20th of next month\

CMP-08 Tax Payment by Composition Dealers Three-monthly 18th of the next month ending the quarter

GSTR-4 Annual Returns for Composition Dealers Yearly April 30 of the next fiscal year

GSTR-9 GSTR 9 Annual Return Yearly December 31 of the next financial year

(For General Taxpayers)

GSTR-9 is mandatory for all ordinary taxpayers whose turnover is more than ₹2 crore (though exemptions have been available for up to ₹5 crore). To track GST registration and filing for a long time, it is necessary to file GSTR-9.

GST Filing Tips and Ways to Avoid GST Filing Mistakes

Checking GSTR-2B: Before claiming ITC in GSTR-3B during GST portal filing, always match GSTR-2B. This is the biggest mistake that the notice makes.

'NIL' Returns: Even if you have not done any business during any period, it is mandatory for you to file 'NIL' GST Tax.

Late Fees: Late filing incurs a penalty of ₹50 (non-NIL return) or ₹20 (NIL return) per day, so strictly adhere to the GST return due date.

Monthly/Quarterly Selection (QRMP Scheme): The QRMP (Quarterly Return Monthly Payment) scheme is available for small businesses (GST filing for proprietorship and small businesses) at a turnover of up to ₹5 crore. It requires filing returns quarterly, but taxes have to be submitted monthly by PMT-06 invoice.

Conclusion: Compliance is the Key to Success

Filing GST tax may seem complicated at first, but it's proof that your business is in order. By filing GST return online at the right time, you not only ensure legal compliance but also reduce your capital expenses by taking full advantage of input tax credit in GST. Considering the rules of the GST tax filing guide 2025, prioritize your filing and provide your business with a trustworthy and strong financial foundation.

Check all your pending returns today and complete GST portal filings on time!

FAQ Section: GST Tax Filing

Q1. Is it necessary to file GST tax even without sales?

A. Yes, absolutely. GST registration and filing is mandatory. If you have not made any sales or purchases in a month or quarter, it is still mandatory for you to file 'NIL' GST Tax. Both GSTR-1 and GSTR-3B will have to file 'NIL' returns to avoid penalty (late fees) and maintain a good compliance record.

Q2. What is Input Tax Credit (ITC) and how do I claim it?

A. Input Tax Credit (ITC) means the GST that you paid when purchasing goods or services for your business. You can deduct this tax paid from your final tax liability (which you charge customers on your sales). To claim it, you need to enter the correct amount of ITC in Table 4 of GSTR-3B, which must match with your GSTR-2B statement.

Q3. What is the due date for filing GSTR-1 and GSTR-3B?

A. The due date for GSTR-1 filing is the 11th of the next month for the monthly filer and the 13th of the month following the quarter for the quarterly filer. The due date for GSTR-3B filing is the 20th of the following month for the monthly filer, while for the quarterly filer under the QRMP scheme, it is the 22nd or 24th (depending on the state).

Q4. If my turnover is less than ₹5 crore, which return can I file?

A. If your turnover is less than ₹5 crore, you can choose the QRMP (Quarterly Return Monthly Payment) scheme. In this scheme, you have to file both GSTR-1 and GSTR-3B quarterly, but for the first two months, the tax has to be paid monthly through challan (PMT-06). This is a great simplification for GST filing for small business.

Q5. How to Make GST Tax Payment Online?

A. For GST Tax Payment, first of all, you have to select the option of 'CREATE CHALLAN' while filing GSTR-3B. Fill in the required tax amount in the challan and select the payment method (such as net banking, NEFT/RTGS, or Over-The-Counter). Net banking is the fastest way. After successful payment, you will get a CPIN (Common Portal Identification Number) and BRN (Bank Reference Number), which will be credited to your cash ledger and used for GSTR-3B filing.

Q6. What is GSTR-9 Annual Return?

A. GSTR 9 annual return is an annual summary return that all general taxpayers have to file. It contains a consolidated summary of all the returns filed in GSTR-1 and GSTR-3B during the entire financial year. This ensures that any monthly or quarterly returns you have filed throughout the year are correct and match your books of accounts. Its due date is December 31 of the next financial year.

GSTR-3B