GST Interest Calculation: Section 50
Last updated: 2 July 2026 · 5 min read
If you pay GST after the due date, interest applies under Section 50 of the CGST Act. This is separate from the late fee for filing returns late.
The rate and formula
The standard rate is 18% per annum, charged on the net tax paid late for the number of days of delay:
Interest = Tax × 18% × Days ÷ 365
Example: ₹10,000 paid 30 days late → 10,000 × 0.18 × 30 ÷ 365 = ₹147.95. Estimate yours with the GST interest calculator.
When 24% applies
A higher rate of 24% per annum applies in specific situations — most notably where input tax credit is claimed in excess or output tax liability is under-declared and later reduced. It does not apply to ordinary late payment.
Net cash liability
Interest is generally computed on the portion of tax discharged in cash (net of eligible input tax credit) for delayed GSTR-3B payments, which reduces the base on which interest is charged.
FAQ
What is the GST interest rate?
18% per annum under Section 50 on tax paid late; 24% in specific ITC/under-declaration cases.
Related: GST late fee rules, interest calculator, common mistakes.