GST interest and late fees

Interest and late fee are two different charges

You can owe both for the same month: a late GSTR-3B means the tax in it was paid late too.

How interest is worked out

Interest on delayed payment is charged at the rate notified under Section 50, currently 18% per year. It runs from the day after the due date until the day you pay. Since the law was amended, interest on late filing is charged on the part of the tax paid through the cash ledger (net of eligible ITC), not on the gross liability.

Example. Your GSTR-3B for a month shows tax of ₹1,60,000, of which ₹1,00,000 is set off with ITC and ₹60,000 is paid in cash. You file and pay 20 days late.

• Interest = ₹60,000 × 18% × 20 ÷ 365 = ₹591.78, split between CGST and SGST (or IGST) in proportion to the cash paid.

Interest on input tax credit that was wrongly availed is charged only on the part actually used, at the notified rate (18% at present — check the current CGST notification). Rates are set by notification; confirm the current rates on cbic-gst.gov.in.

How late fees are worked out

For GSTR-3B and GSTR-1, the standard late fee is ₹50 per day (₹25 CGST + ₹25 SGST), and ₹20 per day (₹10 + ₹10) when the return is a nil return. The total is capped, and the caps are lower for smaller businesses based on turnover.

Example. A GSTR-3B with tax due is filed 12 days late: 12 × ₹50 = ₹600 (₹300 CGST + ₹300 SGST). If it were a nil return: 12 × ₹20 = ₹240.

GSTR-1 late fees are not collected in GSTR-1 itself; the portal adds them to the next GSTR-3B. The annual return GSTR-9 has its own per-day fee and cap linked to turnover. Caps and per-day amounts are changed by notification from time to time, so check gst.gov.in for the figures that apply to your period. Due dates are covered in GSTR-1 due dates and late fee.

How you pay them

1. The portal auto-calculates the late fee in GSTR-3B; interest is partly auto-calculated and editable.
2. Check the interest figure against your own calculation. Add interest for any earlier short payment you are clearing now.
3. If the cash ledger is short, create a challan (PMT-06) under the interest and fee heads; see GST payment challan.
4. Offset and file. ITC cannot be used for interest or late fee.

Situations that quietly create interest

• Sales missed in a month and added later. The tax for that sale was due in the original month. Interest runs from that due date.
• ITC claimed early before the invoice appears in GSTR-2B, then reversed. If the credit was used, interest can apply.
• Reversal under the 180-day rule. See ITC reversal and the 180-day rule.
• Paying into the wrong head (CGST instead of IGST). The IGST stays unpaid until you move the money across.

Also note that the law now bars filing a return after three years from its due date, so very old pending returns cannot simply be filed late with a fee.

How to avoid them

• Close the month's sales and purchases in your books by the 5th–7th, not on the due date.
• Keep enough balance in the cash ledger before the due date, especially during month-end bank holidays.
• File a nil return even when there is no business; the fee is still payable if you do not.
• Note waiver or amnesty notifications, which have reduced fees in the past for specific periods.

This is general information, not tax advice.

Closing the month faster with Cashflow OS

Late filing usually comes from books that are not closed on time. Cashflow OS shows sales, purchases and cash and bank from your Tally data on the phone, and its GSTR-1 and GSTR-3B views let the owner check the month's figures before the accountant files. The returns, interest and late fees are still handled on the GST portal.