🧾 How to File GST Returns in Mumbai: GSTR-1 and GSTR-3B

📍 Introduction

Filing GST returns is mandatory for every registered business in Mumbai. Among the most important returns to file are GSTR-1 (outward supplies) and GSTR-3B (summary return). Whether you're a small business owner or a large enterprise, knowing how to file these returns correctly can save you from penalties and ensure smooth tax compliance. 💼✅

📌 What is GSTR-1?

📊 GSTR-1 is a monthly or quarterly return that captures details of all outward supplies (sales) made by the taxpayer.

🔍 Key Points:

• Frequency: Monthly or Quarterly (based on turnover)

• Due Date:

  • Monthly: 11th of the next month

  • Quarterly (QRMP scheme): 13th of the month after the quarter

• Includes:

  • B2B invoices

  • B2C large invoices

  • Debit/Credit notes

  • Export invoices

🧠 Pro Tip: Use offline utility or GST portal to upload JSON files generated from your accounting software.

📌 What is GSTR-3B?

🧾 GSTR-3B is a monthly summary return to declare total outward and inward supplies, ITC claimed, and net tax payable.

📅 Due Date:

• 20th of the next month (monthly filers)

• Staggered for QRMP scheme (22nd/24th)

💡 Important Info to Fill:

• Outward taxable supplies

• Inward supplies under reverse charge

• ITC claimed

• Tax payment details

🚨 Note: GSTR-3B is not invoice-wise but a summary return. You must pay the tax before filing GSTR-3B.

🛠️ How to File GSTR-1 & 3B on the GST Portal

Step-by-Step Guide:

1. 🔐 Login to the GST portal using your credentials.

2. 🧾 Go to Returns Dashboard

3. 📅 Select Financial Year and Return Filing Period

4. 📂 Choose GSTR-1 or GSTR-3B

5. 🧮 Fill in required sections (B2B, B2C, Exports, ITC, etc.)

6. ✅ Preview, Validate, and Submit

7. 💳 Pay taxes via challan (for GSTR-3B)

8. 🔐 Use DSC or EVC to file

📍 Local Tip for Mumbai Businesses

🏢 Mumbai-based businesses often deal in inter-state supplies and exports. Make sure your HSN codes, export documentation, and E-invoicing compliance are always updated.

📤 If you're a QRMP scheme user, you can use the Invoice Furnishing Facility (IFF) for GSTR-1.

🎯 Common Mistakes to Avoid

🚫 Incorrect invoice dates
🚫 Not matching sales and ITC
🚫 Missing reverse charge entries
🚫 Late filing (leads to heavy late fees & interest)

💬 Conclusion

Whether you're a CA, business owner, or freelancer in Mumbai, GSTR-1 and GSTR-3B filing is your gateway to GST compliance. Avoid penalties, claim your rightful ITC, and stay ahead of deadlines by filing accurately and on time.