GST Late Fee & Interest Calculator in Excel

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Last updated: 27 June 2026 · Late-fee and interest rules for GSTR-1, 3B and 9.

To build a GST late-fee and interest calculator in Excel, multiply the days of delay by the daily late fee (₹50 for a return with tax, ₹20 if nil), cap it by your turnover band, and add interest at 18% per annum on any tax paid late. With the due date and filing date in two cells, =MAX(0, FilingDate - DueDate) gives the days, and the rest is a few MIN/IF formulas.

Key takeaways

Late fee: ₹50/day (₹25 CGST + ₹25 SGST) for a return with liability; ₹20/day (₹10 + ₹10) for a nil return.
Caps depend on turnover (AATO): from ₹500 (nil) up to ₹10,000 for turnover above ₹5 crore.
Interest is 18% p.a. on net tax paid late (24% p.a. on wrongly-availed ITC reversed).
Days of delay = filing date − due date, never below zero: =MAX(0, Filing - Due).
Late fee is paid in cash — it cannot be set off from the ITC ledger.
GSTR-9 has its own slab: ₹200/day with caps tied to turnover (0.04%–0.5% of state turnover).

Fact box. GST late fee for GSTR-1/3B is ₹50 per day (₹25 CGST + ₹25 SGST) for returns with tax, and ₹20 per day (₹10 + ₹10) for nil returns, subject to a maximum cap based on annual aggregate turnover. Interest on late tax is 18% per annum. (Source: CGST Act, Sections 47 & 50; CBIC notifications.)

How is the GST late fee calculated?

Late fee is a per-day charge from the due date to the filing date, then capped by your turnover band.

Return type	Per day	Heads
With liability	₹50	₹25 CGST + ₹25 SGST
Nil return	₹20	₹10 CGST + ₹10 SGST

Maximum caps (non-nil) by aggregate annual turnover:

AATO	Maximum late fee
Nil liability	₹500 (₹250 + ₹250)
Up to ₹1.5 crore	₹2,000
₹1.5 cr – ₹5 cr	₹5,000
Above ₹5 crore	₹10,000

What are the Excel formulas?

Set up input cells: B1 due date, B2 filing date, B3 per-day fee, B4 cap, B5 tax due, B6 interest rate (18).

Days late    =MAX(0, B2 - B1)
Raw late fee =Days * B3
Late fee     =MIN(RawLateFee, B4)
Interest     =B5 * B6/100 * Days/365
Total payable=LateFee + Interest

MAX(0, …) stops negative days when you file early; MIN(…, cap) enforces the turnover cap. Divide the interest by 365 because the 18% rate is annual and you're charging it for the days of delay.

Fact box. GST interest under Section 50 runs at 18% per annum on the net tax paid late, computed for the actual number of days of delay. Late fee, unlike interest, must be paid in cash and cannot be discharged from the Input Tax Credit ledger. (Source: CGST Act, Section 50; CBIC.)

How do I handle a nil return and the turnover cap?

Drive the per-day fee and cap from two lookups so one calculator handles every case:

Per-day fee  =IF(TaxDue=0, 20, 50)
Cap          =IF(TaxDue=0, 500, LOOKUP(AATO, {0,15000000,50000000}, {2000,5000,10000}))

Here the cap LOOKUP reads turnover in rupees: up to ₹1.5 crore → ₹2,000, ₹1.5–5 crore → ₹5,000, above ₹5 crore → ₹10,000. Swap the thresholds to your own bands if you prefer a clearer named table.

What about GSTR-9 (annual return)?

GSTR-9 uses a different slab — ₹200/day (₹100 + ₹100) — with caps tied to turnover:

AATO	Per day	Cap
Up to ₹5 crore	₹50	0.04% of state turnover
₹5 cr – ₹20 cr	₹100	—
Above ₹20 crore	₹200	0.5% of state turnover

Use the same Days × per-day then MIN(cap) pattern, swapping in the GSTR-9 figures above. (Source: CBIC Notification 07/2023.)

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Frequently asked questions

What is the late fee for GSTR-3B? ₹50 per day (₹25 CGST + ₹25 SGST) for a return with tax, or ₹20 per day for a nil return, capped by your turnover band.

What is the late fee for a nil GST return? ₹20 per day (₹10 CGST + ₹10 SGST), with a maximum of ₹500 (₹250 + ₹250).

What interest applies for late GST payment? 18% per annum on the net tax paid late, calculated for the actual days of delay. Wrongly-availed ITC carries 24% per annum.

Can I pay the GST late fee using ITC? No. Late fee must be paid in cash; it cannot be set off against the Input Tax Credit ledger.

How do I calculate days of delay in Excel? Subtract the due date from the filing date and floor at zero: =MAX(0, FilingDate - DueDate).

Sources

CGST Act, Section 47 (late fee) and Section 50 (interest) — cbic-gst.gov.in.
CBIC notifications on late-fee caps by turnover (07/2023, 19/2021).

General information, not professional advice. Verify on the official portal for your case. Reviewed by a Chartered Accountant; last updated 27 June 2026.