GST Interest Calculator
Calculate interest on late payment of GST under Section 50. Supports 18% (late payment) and 24% (excess ITC) rates.
If filled, this overrides the dates above.
Also need to calculate late fee? Use our GST Late Fee Calculator.
Convert to ExcelGST Interest Rates Under Section 50
| Section | Scenario | Rate |
|---|---|---|
| 50(1) | Tax paid after the due date | 18% per annum |
| 50(3) | Excess or wrongful ITC claimed and utilized | 24% per annum |
How GST Interest is Calculated
Formula: Interest = Tax amount × Rate × Days late ÷ 365
Example: Rs. 1,00,000 tax paid 30 days late
Tax amount: Rs. 1,00,000
Interest rate: 18% per annum
Days late: 30
Interest = 1,00,000 × 18/100 × 30/365 = Rs. 1,479.45
CGST interest: Rs. 739.73 | SGST interest: Rs. 739.73
Key Points About GST Interest
- Net tax liability — Interest is calculated on the net amount (after ITC adjustment), not the gross liability. This was clarified retrospectively from July 1, 2017.
- Automatic liability — Interest is self-assessed. You must calculate and pay it yourself when filing a late return.
- Separate from late fee — Late fee (Rs. 50/day) is for filing the return late. Interest (18% p.a.) is for paying the tax late. Both apply simultaneously.
- No cap — Unlike late fees, there is no maximum cap on interest. It accrues for the entire period of delay.
- Paid in cash only — Interest must be paid through the electronic cash ledger. It cannot be set off against ITC.
GSTR-3B Due Dates (for counting days late)
To find the number of days late, count from the day after the GSTR-3B due date to the date the tax is actually paid. The standard due dates:
| Filing type | Return period | Due date |
|---|---|---|
| Monthly (turnover > ₹5 cr, or opted monthly) | Each month | 20th of the next month |
| QRMP — Category X states | Each quarter | 22nd of the month after the quarter |
| QRMP — Category Y states | Each quarter | 24th of the month after the quarter |
Example: GSTR-3B for May (monthly) is due 20 June. Tax paid on 20 July is 30 days late.
How to Pay GST Interest
GST interest is self-assessed — the portal does not auto-charge it, so you must compute and pay it yourself. Two routes:
- Through the next GSTR-3B — report the interest in Table 5.1 and pay it in cash via the electronic cash ledger when you file. This is the normal route.
- Form DRC-03 — for a voluntary payment made outside the return (e.g. after a notice or a self-spotted error).
Interest is always paid in cash; it can never be discharged using input tax credit.
Quick Interest Reference (18% p.a.)
Approximate interest at 18% per annum for common tax amounts and delays:
| Tax amount | 15 days | 30 days | 60 days | 90 days |
|---|---|---|---|---|
| ₹ 10,000 | ₹ 74 | ₹ 148 | ₹ 296 | ₹ 444 |
| ₹ 50,000 | ₹ 370 | ₹ 740 | ₹ 1,479 | ₹ 2,219 |
| ₹ 1,00,000 | ₹ 740 | ₹ 1,479 | ₹ 2,959 | ₹ 4,438 |
| ₹ 5,00,000 | ₹ 3,699 | ₹ 7,397 | ₹ 14,795 | ₹ 22,192 |
These are indicative. Use the calculator above for the exact figure on your tax amount and days late.
GST Interest Calculator in Excel
To compute GST interest in a spreadsheet, put the tax amount, rate, and the two dates in cells and use a single formula:
Days late (A2): =B2-C2 (payment date − due date)
Interest: =D2*E2%*A2/365 where D2 = tax amount, E2 = rate (18 or 24)
CGST = SGST = interest ÷ 2: =F2/2
Download the ready-made Excel template — the formula is already wired up. Fill the amber cells (tax amount, rate, due date, payment date) and the interest, plus the CGST/SGST split, calculates itself. It includes the Section 50 rate reference (18% on late payment, 24% on wrongful ITC). Free, no signup.
Interest vs Late Fee
These are two separate charges. Interest (this page) is 18% per annum on tax paid after the due date. The late fee is a fixed per-day charge for filing the return late — a different calculation entirely. Both can apply at once. To work out the filing penalty, use the GST Late Fee Calculator.
Related Tools & Guides
- GST Late Fee Calculator — calculate penalty for late filing
- GST Calculator — add or remove GST with CGST/SGST/IGST breakdown
- Verify GST Number — validate any GSTIN
- GST Invoice Reader — extract invoice fields to Excel
- GSTR-9 Annual Return Guide — reconcile the year before filing
- GSTR-2B Reconciliation in Excel — match ITC before it affects your liability
Processing GST Invoices?
Upload your GST invoice PDF and get all fields extracted into Excel automatically.
Convert to ExcelFrequently Asked Questions
What is the interest rate on late payment of GST?
18% per annum under Section 50(1) for tax paid after the due date. 24% per annum under Section 50(3) for excess or wrongful ITC that is both claimed and utilized. Interest is on the net tax liability (after ITC adjustment), not the gross.
How is GST interest calculated? (formula)
Interest = Tax amount × Interest rate × Number of days late ÷ 365. Days are counted from the day after the due date up to the date the tax is actually paid.
Is GST interest calculated on gross or net tax liability?
On the net tax liability — the amount payable in cash after adjusting available ITC. A proviso to Section 50(1) confirms this, applying retrospectively from July 1, 2017.
Is there a cap on GST interest?
No. Unlike the late fee, GST interest has no maximum cap. It keeps accruing at 18% per annum for the entire period of delay until the tax is paid.
What is the difference between GST late fee and interest?
Late fee is a fixed penalty for filing the return late (Rs. 50/day, Rs. 20/day for nil). Interest is charged on the tax amount paid late (18% p.a.). Both can apply at the same time.
What is the GSTR-3B due date used to count days late?
For monthly GSTR-3B filers, the 20th of the following month. Under the QRMP scheme it is the 22nd or 24th of the month after the quarter, depending on the state. Interest runs from the day after this date until the tax is paid.
How do I pay GST interest?
It is self-assessed. Most taxpayers pay it through the next GSTR-3B (Table 5.1, in cash via the electronic cash ledger). For a voluntary payment outside the return, use Form DRC-03. Interest cannot be paid using ITC — it must be paid in cash.