Days late × a gazette number
Section 47 late fee plus section 50 interest. Nil GSTR-3B: ₹20/day capped at ₹500 in this sketch. Other: ₹50/day (₹25 CGST + ₹25 SGST) capped at ₹5,000. Interest 18% p.a. × days/365 on net tax unpaid. The GST Council has changed caps; if your portal shows a different fee, the portal wins.
Worked example: 12 days, tax ₹40,000, not nil
Fee min(5000, 50×12) = ₹600. Interest 40000 × 0.18 × 12/365 ≈ ₹237. Total ~₹837 plus whatever the portal rounds.
Questions
Are my numbers uploaded?
No. Arithmetic stays in this tab. Remember writes this browser only.
Can I share the inputs?
The URL hash (#) stores fields. Copy the address bar. Nothing is sent as a query string to a server of ours.
Is this a filing?
No. Print the worksheet. Argue with payroll or a CA. Do not paste this into an ITR as authority.
GSTR-1 vs 3B?
This sketch is the 3B-style daily fee + s.50 interest on net tax. GSTR-1 late fee has its own notifications.
18% or 24%?
s.50: 18% on unpaid tax; higher rate for wrongly availed ITC in some cases — not this box.