If you export services internationally, filing a Letter of Undertaking (LUT) on the GST portal is the most important annual GST action you'll take. Without it, you either pay 18% IGST on every international invoice or get stuck in a refund cycle. This guide covers the exact steps.
What Is LUT and Why You Need It
LUT (Letter of Undertaking) is a declaration filed on the GST portal by service exporters undertaking to comply with GST export requirements without paying IGST upfront.
Without LUT: You must pay 18% IGST on every export service invoice and then claim a refund from the GST department. This creates cash flow problems and administrative overhead.
With LUT: Your international service invoices are zero-rated. No IGST charged, no IGST refund required. Clean.
Who needs it: Any GST-registered Indian business exporting services to international clients.
When to file: Before the start of each financial year (i.e., before April 1). If you missed filing before April 1: file immediately. LUT is valid from the date of acceptance.
Eligibility to File LUT
You can file LUT if:
- You are GST registered
- You are an exporter of services (or goods) to international clients
- You have NOT been prosecuted for any offence under CGST Act or IGST Act with a tax amount of ₹2.5 crore or above in the preceding 5 years If you have a prosecution above ₹2.5 crore: You must file a Bond instead of LUT. This applies to very few businesses. Most Indian service exporters qualify for LUT.
Step-by-Step: Filing LUT on GST Portal (2026)
Step 1: Log in to GST Portal
Go to gst.gov.in → Login with your GSTIN and credentials.
Step 2: Navigate to LUT Filing
Services → User Services → Furnish Letter of Undertaking (LUT)
Step 3: Select Financial Year
Select the financial year for which you're filing LUT. For FY 2025-26: select 2025-26. For FY 2026-27: select 2026-27.
Step 4: Fill in LUT Details
The form will ask for:
- Witnesses: Two witnesses required. Name, occupation, and address of each witness. These are typically your CA and one other trusted person (business partner, employee).
- Place: Your place of business
- Self-declaration checkbox: Confirm you meet LUT eligibility requirements
Step 5: Attach Documents
Documents required:
- LUT of previous year (if applicable, attach the previously accepted LUT)
- Copy of GST registration certificate
- PAN card of authorised signatory
Step 6: Sign Digitally and Submit
- DSC (Digital Signature Certificate): If your company is a company or LLP, DSC may be mandatory
- EVC (Electronic Verification Code): For proprietors and partnership firms, EVC via Aadhaar OTP is acceptable Sign and submit.
Step 7: Acknowledgement
On submission, the GST portal generates an ARN (Application Reference Number). Your LUT is considered filed from this date.
Processing: GST officer reviews and formally accepts. Typically 1-3 business days. Portal shows status as "Approved."
After Filing LUT: What Goes on Every International Invoice
Once LUT is accepted, include this on every international service invoice:
Export of Services — IGST @ 0% (Zero Rated under Section 16 of IGST Act, 2017 — LUT Reference: [Your LUT ARN] for FY [Year])
Common LUT Filing Mistakes
1. Filing too late. LUT should be filed before April 1. Filing in June means your April-May invoices may not have been covered. File immediately if you've missed the deadline.
2. Wrong financial year selected. The LUT is year-specific. Ensure the correct FY is selected before submission.
3. Witness details incorrect. GST officer may reject if witness details are incomplete. Include full name, occupation, and complete address.
4. Not downloading the accepted LUT. After approval, download and save the accepted LUT certificate. You'll need the ARN number for invoices and possibly for bank/FIRA documentation.
FAQ
What is LUT in GST for service exporters? Letter of Undertaking filed on GST portal allowing service exporters to issue zero-rated international invoices without paying 18% IGST upfront. Must be filed annually before April 1.
What happens if I export services without filing LUT? You must pay 18% IGST on your international invoices and later claim a refund from the GST department. Refund process is time-consuming and creates cash flow burden.
Can I file LUT after April 1? Yes. File immediately if you've missed. LUT is valid from the date of acceptance, not retrospectively. Invoices issued before acceptance may require 18% IGST treatment — consult your CA.
Do I need DSC to file LUT? Companies and LLPs: yes, DSC typically required. Proprietorships and partnerships: EVC via Aadhaar OTP is acceptable.