What Is GSTR-3B and How to File It: Complete Guide with Practical Examples for Accurate GST Compliance

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by

Himanshu
in

GSTR-3B is one of the most important GST return forms filed monthly or quarterly by businesses in India. It summarizes outward supplies, inward supplies, input tax credit (ITC), and tax liability for a given period. Every GST-registered business must file GSTR-3B to stay compliant, avoid penalties, and maintain accurate tax records. This comprehensive blog explains what GSTR-3B is, how to file it, common mistakes to avoid, and three practical examples with figures to help you understand the process easily.

With over 1.4 crore active GST taxpayers, GSTR-3B is the most frequently filed GST return in India. Whether you are a business owner, accountant, GST practitioner, or student learning taxation, this guide will give you complete clarity.

What Is GSTR-3B?

GSTR-3B is a monthly or quarterly self-declared summary return in which taxpayers report:

  • Outward supplies (sales)
  • Inward supplies (purchases)
  • Input tax credit (ITC)
  • Tax payable
  • Tax paid

It is not invoice-wise; it is summary-based. This makes it faster and simpler compared to GSTR-1 (invoice-wise reporting).

Who Must File GSTR-3B?

Every regular taxpayer registered under GST must file GSTR-3B, including:

  • Proprietorship firms
  • Partnerships
  • LLPs
  • Companies (Pvt Ltd, Ltd)
  • E-commerce sellers
  • Service providers
  • Traders
  • Manufacturers

Businesses under the QRMP Scheme file GSTR-3B quarterly instead of monthly.

Due Dates for Filing GSTR-3B

CategoryGSTR-3B Due Date
Monthly filers20th of the next month
Quarterly (QRMP)22nd or 24th of next month (state-wise)

Late filing attracts late fees and interest.

Importance of Filing GSTR-3B

Filing GSTR-3B helps:

  • Declare GST liability accurately
  • Claim eligible Input Tax Credit (ITC)
  • Maintain compliance
  • Avoid penalties
  • Ensure GSTR-2B ITC matches
  • Enable e-way bill generation

Non-filing may lead to:

  • Late fees up to ₹10,000 per return
  • 18% interest on tax
  • Blocking of e-way bill
  • Blocking of ITC

Sections in GSTR-3B

Below is a table summarizing all important sections in GSTR-3B:

SectionDescription
3.1(a)Outward taxable supplies (other than zero-rated and exempt)
3.1(b)Outward supplies (zero-rated)
3.1(c)Other outward supplies (nil, exempt, non-GST)
3.1(d)Inward supplies liable to RCM
3.1(e)Non-GST outward supplies
4Input Tax Credit (ITC)
5Interest and late fee

How to File GSTR-3B Step-by-Step

Here is the complete process broken down in detail.

Step 1: Calculate Outward Supplies

Gather monthly or quarterly sales data:

  • Taxable sales
  • Zero-rated exports
  • Exempt sales
  • Non-GST supplies

Ensure correct tax rate: 5%, 12%, 18%, 28%

Step 2: Calculate Input Tax Credit (ITC)

Eligible ITC comes from:

  • Purchases
  • Expense invoices with GST
  • Import of goods
  • Reverse charge purchases

Types of ITC:

  • IGST
  • CGST
  • SGST

Ensure ITC is reflected in GSTR-2B to avoid mismatch.

Step 3: Calculate Reverse Charge Liability (RCM)

RCM applicable on:

  • Transport services
  • Legal services
  • GTA services
  • Import of services
  • Purchase from unregistered supplier (specific cases)

RCM tax must be paid in cash, but ITC can be claimed later.

Step 4: Fill Details in GSTR-3B Form

Fill each section carefully:

3.1 – Details of Outward Supplies

Enter taxable value and GST breakup.

3.2 – Inter-State Supplies

Report supplies made to:

  • Unregistered persons
  • Composition taxpayers
  • UIN holders (embassies)

4 – Eligible ITC

Enter:

  • ITC available
  • ITC reversed
  • Net ITC claimed

5 – Tax Payment

Compute:

  • IGST
  • CGST
  • SGST
  • Cess

Step 5: Pay Taxes

Tax must be paid using:

  • GST cash ledger
  • GST credit ledger

Sequence rule:

  • IGST credit first
  • Then CGST and SGST

Step 6: Submit and File GSTR-3B

Once all details are filled:

  1. Click Save
  2. Click Submit
  3. Click File with DSC/EVC

After filing, an ARN number is generated.

Three Practical Examples of GSTR-3B Filing

These examples include real figures for better understanding.

EXAMPLE 1: Normal Taxable Business

A trader in Delhi has:

  • Taxable sales: ₹5,00,000 @18%
  • Purchase ITC: ₹60,000 IGST

Step-by-Step Calculation:

Outward tax:

  • 18% of 5,00,000 = ₹90,000
    CGST = ₹45,000
    SGST = ₹45,000

ITC available:

  • IGST ITC = ₹60,000

Set off:

  • IGST ITC → CGST + SGST
  • Adjust IGST 60,000 against CGST 45,000 and SGST 15,000

Remaining liability:

  • SGST payable = ₹30,000

Final payable:

  • CGST = 0
  • SGST = ₹30,000

This is the value to be paid in GSTR-3B.

EXAMPLE 2: Business with RCM Supply

A service provider in Mumbai:

  • Taxable sales: ₹3,00,000 @18%
  • ITC available: ₹20,000
  • RCM GTA service: ₹10,000 (5% GST)

RCM tax:

  • 5% of 10,000 = ₹500 IGST

Tax payable on sales:

  • 18% of 3,00,000 = ₹54,000
    CGST = ₹27,000
    SGST = ₹27,000

Total liability:

  • IGST RCM = ₹500
  • CGST = ₹27,000
  • SGST = ₹27,000

ITC adjustment:

  • ITC cannot be used for RCM

Net payable:

  • IGST = ₹500 (cash)
  • CGST = ₹7,000 (after adjusting 20,000 ITC)
  • SGST = ₹27,000

EXAMPLE 3: Export + Local Sales

A manufacturer in Gujarat:

  • Local sales: ₹4,00,000 @18%
  • Export sales (zero-rated): ₹2,00,000
  • ITC available: ₹70,000 IGST

Tax on local sales:

  • 18% of 4,00,000 = ₹72,000
    CGST = ₹36,000
    SGST = ₹36,000

Export sales:

  • Zero-rated (no GST)

ITC set-off:

  • IGST 70,000 used against CGST & SGST
  • CGST: 36,000
  • SGST: 34,000

Total payable:

  • No cash outflow
  • IGST remaining ITC = ₹70,000 – 72,000 = balance used fully

This business will file GSTR-3B with zero tax payment but full reporting.

Common Mistakes While Filing GSTR-3B

  • Entering wrong outward supplies
  • Claiming ITC not appearing in GSTR-2B
  • Forgetting to report RCM
  • Adjusting ITC incorrectly
  • Late filing
  • Not paying interest

Accuracy in GSTR-3B ensures correct GST compliance.

Best Practices for Accurate GSTR-3B Filing

  • Reconcile sales with books
  • Reconcile ITC with GSTR-2B
  • Avoid negative values
  • Match RCM entries
  • File before due date
  • Maintain monthly summaries

Most businesses that follow monthly reconciliation avoid penalties and notices.

Summary Table: GSTR-3B Key Components

SectionWhat to Fill
3.1Outward supplies (sales)
3.2Inter-state unregistered supplies
4ITC available, reversed, net ITC
5Tax paid and late fees

Final Thoughts

GSTR-3B is one of the simplest yet most crucial GST returns. Filing it accurately every month or quarter ensures compliance, smooth business operations, and correct ITC claim. By understanding outward supplies, ITC, RCM, and tax adjustment rules, businesses can avoid mistakes, mismatches, and penalties. The three examples included in this article provide practical clarity on how to calculate tax liability and file GSTR-3B confidently.

Whether you file returns manually or through accounting software, it is essential to verify all figures with books, invoices, and GSTR-2B before submission. Maintaining proper documentation and monthly reconciliation will help you maintain 100% GST compliance.

Disclaimer

This article is prepared for educational and informational purposes. GST laws, ITC rules, rates, forms, and filing procedures may change based on government updates. Users must verify all details according to the latest GST notifications and guidelines before filing actual returns.