01
Pick the return type
Choose GSTR-3B (with tax), GSTR-1 (sales return, no interest) or a NIL return. This sets the per-day fee and whether interest applies.
GST Late Fee & Interest Calculator
Work out the GST late fee and 18% interest on a late return.
Updated Reviewed by Sajid Hussain· Editor
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Results update in real time as you type — no submit needed.
Your numbers
GST Late Fee & Interest bills sellers in Indian Rupee (INR), so this calculator works in INR — not your selected US Dollar ($). Every figure below matches your real GST Late Fee & Interest statement. Localised USD marketplaces are coming soon.
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Last updated
June 14, 2026
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India GST Tool
What Is a GST Late Fee & Interest Calculator?
This calculator shows what filing a GST return late actually costs — the per-day late fee under Section 47, capped by turnover, plus the 18% interest under Section 50 on the tax paid late.
It adds up both charges. A late return attracts a daily late fee and interest on the tax. The calculator computes each, then the combined total — so there is no surprise when you file.
It applies the right cap. The late fee is ₹50 a day for a normal return and ₹20 for a NIL one, but it stops at a cap that depends on your turnover. The calculator caps it correctly and flags when the cap is reached.
It charges interest the right way. Interest is 18% a year on the net tax paid in cash, day by day. Unlike the late fee, interest has no cap — the calculator shows it growing with the days late, and what each extra day adds.
It covers GSTR-3B, GSTR-1 and NIL. A GSTR-1 is a sales return with no tax, so it gets the ₹50-a-day fee but no interest. A NIL return is ₹20 a day, capped at ₹500. Pick the return type and the calculator applies the right rules automatically.
Quick facts
- Late fee (with supplies)
- ₹50 / day
- Late fee (NIL)
- ₹20 / day
- Fee cap
- ₹500 to ₹10,000
- Interest (GSTR-3B)
- 18% per annum
- GSTR-1
- Fee only, no interest
- Cost of waiting
- Shown day by day
How It Works
Calculate Your GST Late Charges in Three Steps
02
Enter days late and tax
Add the days past the due date, and for a normal return the cash tax and your turnover.
03
See the total cost
See the capped late fee, the interest, and the combined late charges to pay.
Steps to use the GST Late Fee & Interest Calculator: Pick the return type, Enter days late and tax, See the total cost.
The Formula
How GST Late Fee and Interest Are Worked Out
01
Late fee
Fee = min(per-day × days, cap)
The per-day fee (₹50 normal, ₹20 NIL) times the days late, capped by your return type and turnover.
Example: ₹50 × 30 = ₹1,500 (cap ₹2,000)
02
Interest
Interest = tax × 18% × days ÷ 365
Interest at 18% a year on the net tax paid in cash, for the number of days of delay. NIL returns have none.
Example: ₹1,00,000 × 18% × 30/365 ≈ ₹1,479
03
Total late charges
Total = late fee + interest
The combined cost of filing late, on top of the tax itself.
Example: ₹1,500 + ₹1,479 = ₹2,979
Worked Example
Step-by-Step Walkthrough (₹1 lakh tax, 30 days late)
Currency note: the example below uses a benchmark scenario priced in Indian Rupee (INR). Values are converted to US Dollar (USD) at the latest exchange rate so you can compare against your own numbers.
Scenario
A normal GSTR-3B filed 30 days late with $100,000.00 of tax payable, turnover up to ₹1.5 crore.
1
Step 1 · Late fee
₹50 a day for 30 days, within the ₹2,000 cap.
Late fee = $1,500.00
2
Step 2 · Interest
18% a year on $100,000.00 for 30 days.
Interest = $1,479.00
3
Step 3 · Total
Late fee plus interest, on top of the tax.
Late charges = $2,979.00
The takeaway
Filing a $100,000.00 GSTR-3B 30 days late costs $1,500.00 in late fee and $1,479.00 in interest — $2,979.00 extra, for a total of $102,979.00. The late fee caps out, but interest keeps running, so filing sooner always saves money.
Fee caps
GST Late Fee Caps by Return
| Metric | Poor | Average | Good | Excellent |
|---|---|---|---|---|
NIL return (GSTR-3B/1) ₹20/day · ₹250 CGST + ₹250 SGST | ₹500 | |||
GSTR-3B/1 · turnover ≤ ₹1.5 cr ₹50/day · ₹1,000 + ₹1,000 | ₹2,000 | |||
GSTR-3B/1 · turnover ₹1.5–5 cr ₹50/day · ₹2,500 + ₹2,500 | ₹5,000 | |||
GSTR-3B/1 · turnover > ₹5 cr ₹50/day · ₹5,000 + ₹5,000 | ₹10,000 | |||
GSTR-9 annual return ₹200/day · Notification 07/2023 | 0.04%–0.50% of turnover |
Comparison
Calcrux vs Generic GST Calculators
| Feature | Calcrux (Free) | Generic | Manual |
|---|---|---|---|
| Late fee and interest together | |||
| GSTR-3B and GSTR-1 in one tool | |||
| Turnover-based fee caps | |||
| NIL-return handling | |||
| Flags when the cap is reached | |||
| Cost-of-waiting projection | |||
| Total payable incl. tax | |||
| Free, no sign-up required |
Common Mistakes
GST Late Filing Mistakes to Avoid
Thinking the late fee grows forever
Why it matters
The late fee stops at a cap, but people assume it keeps climbing and panic — or assume it is tiny and ignore the interest.
Fix
Know your cap (the calculator shows it). After the cap, interest is what keeps growing.
Forgetting interest has no cap
Why it matters
Interest at 18% runs every day on the tax until paid — it can dwarf the capped late fee over time.
Fix
Pay the tax as soon as possible to stop interest, even if you cannot file everything at once.
Charging interest on gross tax
Why it matters
Interest is on the net cash liability after input tax credit, not the gross tax — using gross overstates it.
Fix
Enter the net tax paid in cash; the calculator applies 18% to that.
Ignoring the NIL-return fee
Why it matters
Even a NIL return attracts ₹20 a day if filed late — people assume nil tax means nil consequence.
Fix
File NIL returns on time too; the ₹500 cap is small but avoidable.
Assuming GSTR-1 is penalty-free
Why it matters
GSTR-1 carries no tax, so people think filing it late is free — but a ₹50-a-day late fee still applies (₹20 for a NIL GSTR-1).
Fix
Select GSTR-1 in the calculator to see its fee. There is no interest, but the fee still mounts up to the turnover cap.
Miscounting the days late
Why it matters
The late period starts the day after the due date and counts every calendar day, including holidays.
Fix
Count from the day after the due date to the filing date — the calculator uses this directly.
Pro Tips
Minimise GST Late Charges
Pay the tax first
Interest runs on the tax, not the fee. Paying the cash tax quickly stops the 18% clock even before you finish filing.
Know your cap
Once the late fee hits its turnover cap, extra days add no more fee — only interest. The calculator shows where you stand.
Watch the waiting cost
The cost-of-waiting chart shows what each extra day adds. Even a week's delay on a large tax bill can run into thousands in interest.
File NIL returns on time
They cost ₹20 a day if late. Setting a reminder avoids the avoidable ₹500.
Watch for amnesty schemes
The government sometimes waives late fees for past periods. If you have old pending returns, check for an active scheme before paying.
Automate the due dates
GSTR-3B is usually due on the 20th (or 22nd/24th for QRMP). A calendar reminder is the cheapest late-fee insurance.
Who Uses This
Who Uses This GST Late Fee Calculator
The GST Late Fee & Interest Calculator works across every stage of the workflow.
Small businesses
A business that missed a GSTR-3B deadline works out the late fee and interest before filing.
Freelancers and consultants
A GST-registered freelancer checks the cost of a late return on a small tax amount.
Accountants and tax practitioners
A practitioner computes late charges for several clients with different turnovers.
NIL-return filers
Someone with no tax in a period confirms the ₹20-a-day fee and ₹500 cap.
Businesses clearing old returns
A taxpayer with pending returns estimates the total late charges across the delay.
Glossary
Key GST Late Filing Terms
Every important term you'll encounter in this calculator and the broader topic.
- Late Fee (Section 47)
- The per-day charge for filing a GST return late — ₹50 for a normal return, ₹20 for a NIL return, capped by turnover.
- Interest (Section 50)
- Interest at 18% a year on the net tax paid late, charged for each day of delay with no upper cap.
- GSTR-3B
- The monthly (or quarterly) summary return for GST, on which late fee and interest are most commonly charged.
- GSTR-1
- The return reporting outward supplies (sales). It carries no tax payment, so a late one attracts the late fee but no interest.
- GSTR-9
- The annual GST return. Filing it late costs ₹200 a day, capped at 0.04%–0.50% of turnover — separate rules from the monthly returns.
- NIL Return
- A return for a period with no sales, purchases or tax. Its late fee is ₹20 a day, capped at ₹500, with no interest.
- Net Cash Liability
- The GST payable in cash after using input tax credit — the base on which interest is charged.
- Late Fee Cap
- The maximum late fee — ₹500 (NIL), or ₹2,000 / ₹5,000 / ₹10,000 by turnover — beyond which the fee does not grow.
Help & answers
Frequently asked questions
Everything you need to know about how the GST Late Fee & Interest Calculator works.
01What is a GST late fee and interest calculator?
It works out the cost of filing a GST return late — the per-day late fee under Section 47 (capped by turnover) and the 18% interest under Section 50 on the tax paid late. Enter the days late, tax and turnover to see the total.
02How much is the GST late fee per day?
For a normal GSTR-3B it is ₹50 a day (₹25 CGST + ₹25 SGST). For a NIL return it is ₹20 a day (₹10 + ₹10). The fee is capped depending on your return type and turnover.
03What is the maximum GST late fee?
A NIL return is capped at ₹500. For a normal return, the cap is ₹2,000 for turnover up to ₹1.5 crore, ₹5,000 for ₹1.5–5 crore, and ₹10,000 above ₹5 crore (each split equally between CGST and SGST).
04How is GST interest calculated?
Interest is 18% per annum on the net tax paid in cash, for the days of delay: interest = tax × 18% × days ÷ 365. For example, ₹1,00,000 paid 30 days late is ₹1,00,000 × 18% × 30/365 ≈ ₹1,479.
05Is there interest on a NIL GST return?
No. A NIL return has no tax liability, so no interest applies — only the late fee of ₹20 a day, capped at ₹500.
06Is there a late fee on GSTR-1?
Yes, but no interest. GSTR-1 is a sales statement with no tax payment, so a late one attracts only the late fee — ₹50 a day (₹20 for a NIL GSTR-1), with the same turnover caps as GSTR-3B. Select GSTR-1 to see it.
07What is the GSTR-9 annual return late fee?
GSTR-9 is charged at ₹200 a day (₹100 CGST + ₹100 SGST), capped at a share of turnover: 0.04% for turnover up to ₹20 crore and 0.50% above it. It uses different rules from the monthly returns this calculator handles.
08How much does each extra day of delay cost?
Until the fee cap, ₹50 a day on a normal return, plus interest. For ₹1,00,000 of tax at 18%, interest alone is about ₹49 a day. Once the late fee caps out, only interest keeps adding up — so paying sooner always costs less.
09Did GST interest calculation change in 2026?
Yes. From the January 2026 tax period, the GST portal charges interest on the net tax due minus the lowest balance kept in your Electronic Cash Ledger over the delay. This calculator assumes the tax stayed unpaid throughout, so it shows an upper-bound figure.
10What is the GST interest rate — 18% or 24%?
The standard rate is 18% a year on delayed tax payment. 24% applies only in specific cases, such as excess input tax credit claimed and reversed. The calculator defaults to 18% and lets you change it.
11Does the late fee keep growing forever?
No. The late fee grows at the per-day rate only until it hits the cap for your turnover. After that it stops — but interest on the tax keeps adding up each day until you pay.
12Is interest charged on the gross tax or net cash?
Interest is charged on the net tax paid in cash — that is, your liability after using input tax credit. The calculator asks for this cash amount so the interest is accurate.
13When does the late period start?
It starts the day after the return's due date and runs until you file and pay. Count every calendar day, including holidays, as days late.
14Is the late fee the same for CGST and SGST?
Yes. The per-day fee and the cap are split equally between CGST and SGST. A ₹50-a-day fee is ₹25 CGST and ₹25 SGST; a ₹2,000 cap is ₹1,000 each.
15Can the GST late fee be waived?
Sometimes. The government occasionally announces amnesty schemes that waive or reduce late fees for past periods. Outside those, the late fee and interest are payable as calculated.
16Is this GST late fee calculator free and accurate?
Yes — it is free and uses the current per-day fees, turnover-based caps, and 18% interest. Confirm any active amnesty scheme and the exact due date before paying, as rules can change.
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