Work out the interest on a late GST payment. Interest runs at 18% per annum on the tax paid late (24% on excess input tax credit claimed), for the number of days of delay.
Interest is charged on the net tax paid in cash after set-off, at 18% per annum from the day after the due date to the date of payment, calculated on a daily (Actual/365) basis. Excess or wrongly-claimed input tax credit attracts 24%.
When GST is paid after the due date, interest under Section 50 of the CGST Act applies at 18% per annum on the amount of tax paid late. A higher 24% per annum rate applies where excess input tax credit was claimed or output tax was under-declared. Interest is worked out day by day, so the exact number of days of delay matters.
How GST interest is calculated
Interest = tax × rate% × days ÷ 365
₹10,000 tax at 18%
Interest
15 days
₹74
30 days
₹148
60 days
₹296
90 days
₹444
Worked example
GST of ₹50,000 paid 45 days late at 18%: interest is 50,000 × 18% × 45 ÷ 365 = ₹1,110.
Interest, late fee and the net cash rule
Interest is separate from the late fee for filing GSTR-3B late. Since 2021, interest is charged only on the portion of tax paid in cash (net of input tax credit), not on the gross liability — so offsetting eligible ITC first reduces the interest base. The rate itself is fixed by law.
Frequently asked questions
What is the interest rate on late GST payment?
18% per annum on tax paid late; 24% per annum where excess input tax credit was claimed.
Is GST interest on gross or net tax?
On the net tax paid in cash after setting off eligible input tax credit.
From when is interest counted?
From the day after the due date until the date the tax is actually paid, on a daily basis.
Is interest the same as the late fee?
No. Interest is for late payment of tax; the late fee is a separate per-day charge for late filing of the return.
Estimates for general guidance, not tax advice. GST provisions can change; confirm the current position and consult a professional.
Written by the CalcPine team · Reviewed for accuracy · Last updated 16 July 2026 · Method: tax × rate% × days ÷ 365 (18% late payment / 24% excess ITC).
