GSTR-3B Late Fees, Interest & Revised Interest Calculation (2026 Updated Guide)

Filing GSTR-3B after the due date can lead to:

• Late fees
• Interest liability
• System-generated interest in the portal
• Possible compliance consequences

From January 2026 tax period onwards, GSTN has introduced important changes in the way interest is calculated in GSTR-3B.

In this guide, we explain everything in simple language with practical examples.

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1️⃣ Due Date of GSTR-3B (Important)

For Regular Taxpayers:

GSTR-3B Due Date = 20th of the next month

Example:

• January return → Due on 20th February
• February return → Due on 20th March

For QRMP Taxpayers:

• Quarterly return filing
• Due Date = 22nd or 24th of the month following the quarter (based on state grouping)

Important: Even if there is no business activity, NIL GSTR-3B must be filed.

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2️⃣ What Happens If GSTR-3B Is Filed Late?

Two Separate Liabilities Apply:

A. Late Fee

B. Interest

Late Fee = Fixed daily penalty

Interest = Calculated on unpaid tax amount

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3️⃣ GSTR-3B Late Fees (Current Structure)

Normal Return: ₹50 per day (₹25 CGST + ₹25 SGST) | Maximum ₹10,000

NIL Return: ₹20 per day (₹10 CGST + ₹10 SGST) | Maximum ₹500

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4️⃣ Example – Late Fee Calculation

Case 1 – Normal Return

Due Date = 20 February

Filed On = 28 February

Delay = 8 Days

Late Fee = 8 × ₹50 = ₹400

Breakup = ₹200 CGST + ₹200 SGST

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Case 2 – NIL Return

Delay = 15 Days

Late Fee = 15 × ₹20 = ₹300

Within ₹500 maximum limit.

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5️⃣ Interest on Delayed GSTR-3B – Legal Position

• Tax paid after due date
• Return filed late with outstanding liability
• Short payment of tax

Standard Interest Rate = 18% per annum

24% in case of wrongful ITC utilisation

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6️⃣ Major Update from January 2026

Interest computation in Table 5.1 now considers:

👉 Minimum Cash Balance available in Electronic Cash Ledger (ECL)

👉 From due date till date of tax payment

This aligns with Rule 88B(1) and Section 50.

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7️⃣ Revised Interest Calculation Formula (2026 Update)

Interest = (Net Tax Liability – Minimum Cash Balance in ECL) × (Number of Days Delayed ÷ 365) × 18%

This gives relief if you already had sufficient balance in cash ledger.

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8️⃣ Practical Example – Before & After 2026

Scenario:

Net Tax Liability = ₹1,00,000

Minimum Cash Balance in ECL = ₹40,000

Delay = 10 Days

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Step 1 – Adjusted Tax Liability

₹1,00,000 – ₹40,000 = ₹60,000

Step 2 – Apply Formula

₹60,000 × (10 ÷ 365) × 18% = ₹296 (Approx.)

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Earlier Method (Without ECL Benefit)

₹1,00,000 × (10 ÷ 365) × 18% = ₹493 (Approx.)

Saving = ₹493 – ₹296 = ₹197

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9️⃣ System-Computed Interest in Table 5.1

• Interest auto-populated
• Non-editable downward
• Can increase if required
• Portal shows minimum interest

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🔟 Tax Liability Breakup Auto-Population

Portal auto-populates Tax Liability Breakup Table based on:

• GSTR-1
• GSTR-1A
• IFF
• Date of supply documents

Path: Login → GSTR-3B Dashboard → Table 6.1

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1️⃣1️⃣ Update in Table 6.1 – Cross Utilization

After IGST ITC is fully utilised, portal allows payment of IGST liability using CGST and SGST ITC in any sequence.

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1️⃣2️⃣ Interest in GSTR-10

If cancelled taxpayer files last GSTR-3B late, interest will be collected through Final Return (GSTR-10).

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1️⃣3️⃣ Common Mistakes

• Paying tax but not filing return
• Ignoring small ECL balances
• Not checking auto-calculated interest
• Assuming portal interest is final
• Filing NIL return late

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1️⃣4️⃣ Practical Advice

• Maintain sufficient cash balance before due date
• File by 18th to stay safe
• Reconcile GSTR-2B monthly
• Verify Table 5.1 interest
• Review liability breakup table

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Conclusion

The January 2026 update brings relief by considering minimum cash balance in ECL. However, late filing still results in late fees, interest liability and system-generated entries. Timely compliance is always more economical.

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Disclaimer

This article is prepared for educational purposes only. For statutory compliance, always refer to the CGST Act, Rules and official GST notifications.

About the Author
Sonia Agarwal is a Registered GST Practitioner (Reg No: 231800001794GPK) with 7+ years of experience in GST compliance, corporate taxation, and audits. She has worked with Deloitte and specializes in practical GST advisory.