Last Updated on August 24, 2026
Here’s the honest answer, and it trips up a surprising number of exporters: there’s no separate “LUT number” issued by the GST portal. What you’re actually looking for is your ARN, the Application Reference Number generated the moment you filed Form GST RFD-11, and that same number doubles as your LUT reference for invoicing. A lot of confusion online, including some genuinely wrong advice floating around forums about a distinct 17-digit “LUT number,” comes from people not realising the ARN is doing double duty.
Worth knowing before we go further: LUT isn’t the only way to export without an IGST hit. You can either export under LUT (or Bond) without paying IGST and claim a refund of unutilised input tax credit later, or pay IGST upfront and claim that back as a refund instead. Most exporters pick LUT because it doesn’t tie up cash while waiting on a refund.
Below is exactly where to find it on the portal, what to do if it’s not showing up where you expect, and what to actually put on your export invoices.
Quick Summary
The reference number for a Letter of Undertaking (LUT) is the Application Reference Number (ARN) generated after the LUT is successfully filed on the GST portal. The ARN is used to track and identify the LUT application and is generally available in the acknowledgement issued by the GST portal. If you have already filed an LUT, you can retrieve its details and acknowledgement from your GST portal account instead of filing a new application simply because the reference number is not readily available.
- ARN is the key reference: The GST portal generates an Application Reference Number (ARN) for the LUT application. The ARN can be used to track or identify the submitted application.
- No separate LUT number is generally required: The ARN and the LUT acknowledgement are the main references available for the submitted LUT.
- Check your GST portal: Filed LUT details and acknowledgements can be accessed through the relevant LUT services under your GST portal login.
- LUT is financial-year specific: An LUT is furnished for a financial year. A fresh LUT should generally be furnished for each financial year in which the exporter intends to supply goods or services without payment of IGST under LUT.
- Check the correct financial year: If you cannot locate an earlier LUT, verify that you are using the correct GSTIN, login credentials, and financial year.
- Download the acknowledgement: The submitted LUT acknowledgement can generally be downloaded or accessed from the GST portal, providing a convenient record of the application and its reference details.
- Export invoices: Export invoices should contain the prescribed export endorsement and other required particulars. The LUT ARN should not be treated as a mandatory invoice field unless specifically required under the applicable rules or circumstances.
Keeping a copy of the LUT acknowledgement and ARN for each financial year can make GST export compliance easier and help you respond quickly if the details are required during reconciliation, refund processing, or a compliance review.
Need Help with LUT Filing or Export GST Compliance?
Kanakkupillai can assist with LUT filing, GST export compliance, refund-related requirements, and other GST services for exporters.
Why This Confuses So Many People
Filing an LUT doesn’t hand you back a certificate with its own unique numbering system, the way a trademark registration or a GST registration certificate would. Instead, the acknowledgement you get after filing RFD-11 is essentially a printout confirming your application, and the ARN printed on it is the only identifying number the system generates. Somewhere along the way, people started calling this the “LUT number” informally, and that’s fine as a nickname; it’s just not a separate, differently-formatted number you need to hunt down elsewhere.
Who Can File an LUT?
Not every exporter qualifies for an LUT. You’re eligible unless you’ve been prosecuted for tax evasion exceeding ₹2.5 crore under the CGST Act, IGST Act, or an earlier indirect tax law. Casual taxable persons and non-resident taxable persons aren’t eligible for an LUT at all.
If you don’t qualify, you can still export without paying IGST, but you’ll need to furnish a Bond along with a bank guarantee (usually up to 15% of the bond value) instead. That’s also why LUT filing is free, while the Bond route carries a bank guarantee cost.
Where to Actually Find It on the Portal
Step 1. Log in to the GST portal
Go to gst.gov.in and log in using your GSTIN, username, and password, the same credentials you’d use for any other filing.
Step 2. Navigate to your submitted LUTs
Click Services, then User Services, then View My Submitted LUTs. This pulls up every LUT you’ve filed from that login, listed by financial year.
Step 3. Locate the relevant financial year
Find the entry for the year you need; each LUT only covers April to March of one specific year, so make sure you’re not looking at last year’s filing by mistake.
Step 4. Open or download the acknowledgement
Click through to view the ARN directly, or download the acknowledgement PDF, which shows your GSTIN, the financial year, the ARN, and the filing date all in one place.
Still can’t locate it? Our experts can help you track it down or file a fresh LUT.
If You Genuinely Can’t Find It Anywhere
- Double-check you’re logged into the correct GSTIN, especially if you manage more than one registration
- Confirm you’re filtering by the right financial year, not the previous or upcoming one
- Check whether the application was actually submitted, and not just saved as a draft, under My Saved Applications
- Search your registered email for the automated confirmation GSTN sends out the moment a LUT is filed
What to Actually Put on Your Export Invoices
Once you’ve got the ARN, that’s what goes on your invoice, typically written as something like “Supply meant for export under LUT, ARN [your number], dated [filing date], without payment of IGST.” There’s no additional certificate number to chase down or add alongside it; the ARN alone is what a buyer, auditor, or GST officer needs to verify the export was genuinely covered under a valid LUT at the time.
Your invoice first needs the exact declaration prescribed under GST invoicing rules: “SUPPLY MEANT FOR EXPORT/SUPPLY TO SEZ UNIT OR SEZ DEVELOPER FOR AUTHORISED OPERATIONS UNDER BOND OR LETTER OF UNDERTAKING WITHOUT PAYMENT OF INTEGRATED TAX.” The ARN and filing date get added on top of that, not instead of it.
Documents and Details You’ll Need
| What You Need | Why |
| GST login credentials for the correct GSTIN | To access the portal and view your filing history |
| The financial year you’re checking | LUTs are filed separately for each year, not carried forward |
| Access to your registered email or mobile | GSTN sends the ARN automatically at the time of filing |
Fees / Cost
There’s no fee for filing an LUT, and equally no fee for retrieving your ARN from a previous filing. This is entirely a self-service lookup on the portal; no professional charges apply unless you’re bringing someone in to help track down a genuinely missing filing or handle a fresh one.
Validity and the Refiling Reminder
LUT is only valid for the financial year you filed it for, April 1 through March 31, and needs to be refiled every year before you raise your first export invoice of that new year. The deadline for FY 2026-27 was 31 March 2026, so if you’re exporting right now without having filed for this year, that’s worth fixing immediately, since any export invoice raised without a valid LUT for the current year technically attracts IGST upfront rather than the zero-rated supply treatment you’re expecting.
What Happens If You Miss the Export Time Limit
Filing the LUT isn’t the end of the compliance chain; it comes with conditions attached. Under Rule 96A of the CGST Rules, goods have to actually leave India within 3 months of the export invoice date. For services, payment needs to land in convertible foreign exchange within 1 year of the invoice date.
Miss either deadline, and the exemption is treated as if it never applied; IGST becomes payable on that invoice, along with interest at 18% per annum calculated from the invoice date itself, not from when the deadline lapsed. Worth building into your tracking, especially with slow-paying overseas clients.
What’s Current on the Portal
The GST portal has been live for FY 2026-27 LUT filings since earlier this year, and the process itself hasn’t changed: Form RFD-11, financial year selection, an optional upload of the previous year’s acknowledgement for reference, and submission via DSC or EVC. What has stayed consistent, and worth repeating since it causes so much confusion, is that the system still only issues an ARN; no separate LUT-specific numbering has been introduced.
One thing worth flagging: companies and LLPs must authenticate the filing using a DSC; EVC (Aadhaar OTP) is only available if you’re filing as a proprietorship or an individual signatory.
Common Mistakes That Cause This Confusion
- Assuming there’s a separate LUT number distinct from the ARN, and searching for one that doesn’t exist
- Quoting last year’s ARN on this year’s invoices, since the two aren’t interchangeable
- Checking submitted applications under the wrong GSTIN when managing multiple registrations
- Not saving the acknowledgement PDF at the time of filing, then struggling to relocate it months later
Why Keeping This Straight Actually Matters
- Avoids invoices going out with an incorrect or expired reference number
- Keeps your zero-rated export treatment defensible if a GST officer asks for proof
- Saves the scramble of hunting for an old filing right when a buyer or auditor asks for it
A Scenario Worth Knowing About
An exporter filed their LUT back in April, saved the acknowledgement somewhere on an old laptop, and months later needs to quote the reference number for a client’s compliance check. They search their email for something labelled “LUT Number” and find nothing, since the confirmation email only mentions an ARN. A quick trip to Services, User Services, View My Submitted LUTs pulls up the exact same number in under a minute, no drama, just a five-minute detour that a bit of prior knowledge would have skipped entirely.
A Few Things Worth Doing Differently
- Download and save the acknowledgement PDF the same day you file, not months later when you actually need it
- Set a reminder for late March each year, since LUTs don’t roll over automatically
- If you manage multiple GSTINs, keep a simple log of which ARN belongs to which registration and year
ARN vs the So-Called “LUT Number”: Clearing It Up
| Term | What It Actually Is | Where You’ll See It |
| ARN | The official reference number generated on filing RFD-11 | Confirmation email, SMS, and the acknowledgement PDF |
| “LUT Number” | An informal nickname for the same ARN, not a separate number | Sometimes used loosely in emails or casual conversation |
| LUT Certificate | The downloadable acknowledgement document itself | Available under View My Submitted LUTs on the portal |
How Kanakkupillai Can Help?
We help exporters track down old LUT filings, file fresh ones before the yearly deadline, and get invoicing references right the first time, so a simple lookup never turns into an afternoon of digging through old emails.
Conclusion
There’s no hidden LUT number waiting to be discovered somewhere; the ARN you received when you filed Form GST RFD-11 is the only reference you need, and it’s sitting right there under View My Submitted LUTs whenever you need to pull it up again. The real habit worth building isn’t finding it once; it’s refiling on time every year and saving the acknowledgement somewhere you’ll actually remember. Get expert help with your LUT filing and export compliance from Kanakkupillai today.
Need help with GST LUT filing or finding your LUT details?
Get expert assistance with LUT filing, GST compliance and export-related GST requirements.
FAQs
1. Is the LUT number different from the ARN?
No, they’re the same thing. The GST portal only generates an ARN when you file Form RFD-11, and that number is what people informally refer to as the LUT number.
2. Where exactly do I find my previously filed LUT on the portal?
Log in, then go to Services, User Services, and View My Submitted LUTs. This shows every LUT filed under that login, along with the ARN and filing date for each financial year.
3. Can I use last year’s LUT reference on this year’s export invoices?
No, a LUT is valid only for the financial year it was filed for. You need a fresh ARN from this year’s filing before raising export invoices under the new year’s LUT.
4. What happens if I can’t find my LUT filing anywhere on the portal?
Check that you’re logged into the correct GSTIN and filtering by the right financial year first. If it’s genuinely missing, it may have only been saved as a draft rather than submitted, in which case you’ll need to file it properly.
5. Do I need to mention the ARN on every single export invoice?
Yes, it’s standard practice to reference your LUT’s ARN on export invoices to show the supply was made without payment of IGST under a valid LUT for that period.
6. Is there a fee to retrieve my LUT details from the portal?
No, viewing or downloading your previously filed LUT acknowledgement is free and available anytime through your GST portal login.
7. Is every exporter eligible to file an LUT?
No. Exporters prosecuted for tax evasion over ₹2.5 crore, and casual or non-resident taxable persons, must furnish a bond with bank guarantee instead.
8. What happens if I don’t export within the time limit after filing an LUT?
Goods must be exported within 3 months of the invoice date (1 year for service payment receipt). Missing this makes IGST plus 18% p.a. interest payable from the invoice date.
Can I file an LUT anytime during the year, or only before it starts?
You can file it anytime before your first export invoice of that financial year; filing in August still validly covers exports from that point forward, though invoices already raised earlier that year without one aren’t retroactively covered.
