GST Interest Calculator
If GST is paid after the due date, interest is charged under Section 50 of the CGST Act at 18% per annum on the tax paid late. Enter the tax amount, the due date and the actual payment date, and this calculator counts the days of delay and shows the interest along with the exact formula used.
Default 18% (Section 50). Use 24% only for the specific cases of excess ITC claimed or output tax under-declared.
Formula & example
Interest = Tax × Rate% × (Days delayed ÷ 365)
Example: ₹10,000 tax paid 30 days late at 18% = 10,000 × 0.18 × 30 ÷ 365 = ₹147.95. Total payable = ₹10,147.95.
FAQ
What is the interest rate on late GST payment?
18% per annum under Section 50 of the CGST Act, on the net tax paid late for the days of delay.
How is GST interest calculated?
Interest = tax × 18% × days ÷ 365. For ₹10,000 paid 30 days late, that is ₹147.95.
When does 24% apply?
24% applies in specific cases such as excess input tax credit claimed or output tax liability under-declared, not to ordinary late payment.
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Last updated: 2 July 2026. Governing rule: Section 50, CGST Act, 2017 (18% p.a.).