GST Return Calculator — Avoid Late Filing Penalties — India 2026
Calculate GST return filing deadlines and potential late fees. Understand GSTR-1 GSTR-3B and annual return requirements for your business.
GST return filing is mandatory for all registered businesses in India. GSTR-1 (outward supplies) is due on the 11th of the following month. GSTR-3B (summary return with tax payment) is due on the 20th. Late filing attracts Rs 50 per day (Rs 25 CGST + Rs 25 SGST) capped at Rs 10000 per return. Additionally 18% interest applies on unpaid tax from the due date. Consistent late filing can lead to GST registration cancellation.
What is the penalty for late GST return?
Late filing: Rs 50/day (Rs 25 CGST + Rs 25 SGST) up to Rs 10000 maximum per return period. For nil returns: Rs 20/day (Rs 10 CGST + Rs 10 SGST) up to Rs 10000. Interest on unpaid tax: 18% per annum from the due date. If GSTR-3B is filed late by 3 months continuously the GST registration may be cancelled by the department.
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GST Calculator
How Tax Calculation Works
Income tax is calculated on your total taxable income after deducting eligible exemptions and deductions from your gross income. The tax is applied progressively — you pay a lower rate on initial income slabs and higher rates only on income that exceeds each threshold. This means moving into a "higher tax bracket" does not mean your entire income is taxed at the higher rate. Understanding marginal vs effective tax rate is crucial: your marginal rate applies only to the last rupee earned, while your effective rate is the average across all slabs.
Tax-Saving Strategies
Under the old regime, maximize deductions: Section 80C allows up to Rs 1.5 lakh through PPF, ELSS, EPF, and life insurance. Section 80D covers health insurance premiums up to Rs 25,000 (Rs 50,000 for senior citizens). Section 80CCD(1B) offers an additional Rs 50,000 deduction for NPS contributions. Home loan interest up to Rs 2 lakh is deductible under Section 24. Under the new regime, the Rs 75,000 standard deduction and lower slab rates may save you more if your total deductions are below Rs 3.75 lakh. Calculate under both regimes before choosing.
Key Information
| Parameter | Details |
|---|---|
| GSTR-1 Due Date | 11th of following month |
| GSTR-3B Due Date | 20th of following month |
| Late Fee (per day) | Rs 50 (Rs 25 CGST + Rs 25 SGST) |
| Late Fee Cap | Rs 10000 per return |
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Use Calculator NowFrequently Asked Questions
What is the penalty for late GST return?
Late filing: Rs 50/day (Rs 25 CGST + Rs 25 SGST) up to Rs 10000 maximum per return period. For nil returns: Rs 20/day (Rs 10 CGST + Rs 10 SGST) up to Rs 10000. Interest on unpaid tax: 18% per annum from the due date. If GSTR-3B is filed late by 3 months continuously the GST registration may be cancelled by the department.
Which GST returns do I need to file?
Regular taxpayer: GSTR-1 (monthly by 11th) + GSTR-3B (monthly by 20th) + GSTR-9 (annual by 31 December). Composition scheme: CMP-08 (quarterly) + GSTR-4 (annual). If turnover is under Rs 5 crore: GSTR-1 can be filed quarterly under QRMP scheme. All businesses must file annual GSTR-9 reconciling monthly returns with books of accounts.
How to file GST returns on time?
Set calendar reminders for the 8th (prepare GSTR-1) and 17th (prepare GSTR-3B) of each month. Use GST accounting software like Tally ClearTax or Zoho that auto-generates returns from your invoices. Reconcile input tax credit monthly to avoid mismatches. For small businesses consider hiring a CA or GST practitioner (Rs 1000-3000/month) to handle filing and compliance.
Which tax regime should I choose — old or new?
Choose the new regime if your total deductions are below Rs 3.75 lakh. Choose the old regime if you claim HRA, 80C (Rs 1.5L), 80D, home loan interest, and NPS totaling more than Rs 3.75 lakh. Salaried employees can switch every year.
Is income up to Rs 12 lakh really tax-free?
Under the new regime for FY 2025-26, income up to Rs 12 lakh is effectively tax-free due to Section 87A rebate. After Rs 75,000 standard deduction, taxable income is Rs 11.25 lakh which qualifies for full rebate. However, income even slightly above Rs 12 lakh loses this entire benefit.
How can I save more tax legally?
Under the old regime, maximize 80C (Rs 1.5L via PPF, ELSS, EPF), 80D (Rs 25K-50K for health insurance), 80CCD(1B) (Rs 50K for NPS), HRA exemption, and home loan interest (Rs 2L under Section 24).
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Last updated: March 2026