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Tax 2026-06-01 8 min read CalcBit Editorial Team

GST Return Filing Guide 2025-26: Due Dates, Forms & Late Fees

Complete guide to GST return filing in India for 2025-26. Learn about GSTR-1, GSTR-3B, GSTR-9, due dates, late fees, and how to file without errors.

Filing GST returns is a crucial compliance requirement for registered businesses in India. This guide covers everything you need to know about GST return filing.

Types of GST Returns

GSTR-1: Monthly/quarterly return for outward supplies (sales)

  • Due date: 11th of next month (monthly) or 13th of month after quarter (quarterly)
  • Contains all sales invoices, debit/credit notes

GSTR-3B: Monthly summary return with payment

  • Due date: 20th of next month
  • Summary of sales, ITC claimed, and tax payment

GSTR-9: Annual return (for regular taxpayers)

  • Due date: 31st December of following financial year
  • Reconciliation of monthly returns

GSTR-9C: Self-certified audit (for turnover > ₹5 crore)

  • Now merged with GSTR-9 in simplified format

Late Filing Penalties

GSTR-3B: ₹50/day (₹25 CGST + ₹25 SGST), maximum ₹10,000

GSTR-1: ₹50/day

Interest: 18% per annum on tax amount

Step-by-Step Filing Process

1. Collect all invoices (sales and purchases)

2. File GSTR-1 with sales details

3. File GSTR-3B with summary and payment

4. Reconcile with GSTR-2A/2B auto-drafted data

5. Claim ITC only on invoices uploaded by suppliers

Use our GST Calculator to verify your tax calculations before filing. For profit analysis, use our Profit Margin Calculator.

Common Mistakes to Avoid

1. Mismatch between GSTR-1 and GSTR-3B

2. Claiming ITC on non-business purchases

3. Wrong HSN/SAC codes on invoices

4. Missing monthly filing deadlines

5. Not reconciling purchase register with GSTR-2A

Documents to Maintain

  • Sales invoices with GST
  • Purchase invoices for ITC
  • Debit/Credit notes
  • E-way bills (for inter-state movement above ₹50,000)
  • Payment challans

Our GST Calculator helps you compute accurate GST amounts for your invoices and returns.

Tags

GST returnGSTR-1GSTR-3BGST filingGST due datestax complianceIndia GST
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CalcBit Editorial Team