What you actually owe when a GSTR-3B return is filed late, and how the interest is computed.

By Kanoons Editorial Team · 5 min read · Last verified 2026-07-26

Filing GSTR-3B after the due date attracts a late fee of ₹50 per day of delay (₹25 CGST + ₹25 SGST) for normal returns, or ₹25 per day (₹12.50 + ₹12.50) for nil returns, subject to turnover-based caps introduced from June 2021.

In addition to the late fee, interest at 18% per annum applies on the net cash tax liability, calculated from the day after the due date until the date of payment. The return itself cannot be filed until any pending late fee for the previous period is cleared, which can create a compounding backlog if left unattended.

Use the GST Late Fee calculator on this site to estimate your exact exposure before filing.