LUT vs IGST Refund 2026: Differences, Process, Examples, Best Practices

$863 billion in exports. 4.6% growth. India just set a new FY26 record despite global headwinds.

If you’re exporting goods or services, that scale also means that GST refunds aren’t just a compliance step for you; they decide how quickly you can reuse your money for operations, hiring, or scaling.

Under Section 16 of the IGST Act, exports are treated as zero-rated supplies, meaning you’re not supposed to carry the tax burden. To make that work, you usually choose between two routes:

• Export under LUT, where you don’t pay IGST upfront.
• Export with IGST payment, where you pay first and claim a refund later.

Both routes eventually lead to refunds, but your experience with them can feel very different.

In this guide, you’ll get a clear view of how both routes work, where each one makes sense, what usually goes wrong, and how you can avoid refund delays.

• With LUT, you can export without paying IGST upfront.
• With the IGST route, you pay tax first and claim the refund later.
• LUT is usually preferred if you want to avoid blocking working capital.
• IGST refunds may feel faster for some exporters because of customs-linked automation.
• Accurate invoices and export documentation are extremely important for both routes.
• FIRA/FIRC documents often become important during GST refund processing and LUT compliance checks.
• Automating export payment documentation can help reduce refund delays and reconciliation effort.

LUT stands for Letter of Undertaking.

It’s a declaration you file on the GST portal that allows you to export goods or services without paying IGST upfront.

Without LUT, you may have to:

1. Pay IGST first.
2. Wait for the refund process.
3. Recover the money later.

With LUT, you skip that upfront tax payment completely.

This is one of the biggest reasons why many exporters prefer the LUT route, especially businesses that want to preserve cash flow.

For example, if you export services worth ₹20 lakhs every month, paying IGST first can temporarily block a significant amount of money. Even if the refund eventually comes back, your working capital stays tied up during that period.

LUT helps you avoid that situation.

Instead of paying tax first, you export directly and later claim refunds for eligible Input Tax Credit (ITC), if applicable.

Most exporters in India can use the LUT route. This includes:

• Goods exporters 
• Service exporters 
• SaaS companies 
• Freelancers working with international clients 
• Consultants and agencies 
• IT companies 
• SEZ suppliers 

For many service exporters, LUT has become the default choice because it simplifies cash flow management.

The process is fairly simple once you understand the flow. Here’s what usually happens:

Step 1: You file LUT on the GST portal.

This gives you permission to export without paying IGST.

Step 2: You raise export invoices without IGST.

Your invoices mention export under LUT.

Step 3: You receive payment from overseas clients.

This is where export payment proof becomes important.

Step 4: You maintain export documentation.

This may include:

• Invoices 
• Bank realization proof 
• FIRA/FIRC 
• Contracts or agreements 

Step 5: You claim a refund of accumulated ITC (if applicable).

If you’ve paid GST on business expenses, you may be able to claim refunds separately.

The biggest reason is simple:

Better working capital

You’re not parking money in taxes while waiting for refunds. This becomes especially useful if:

• You export regularly 
• Your payment cycles are long 
• Your margins are tight 
• You’re scaling internationally 
• You operate a service-based business 

For startups and smaller exporters, preserving liquidity can make a huge difference operationally.

Other reasons include:

Lower cash flow pressure

Especially useful if:

• You’re scaling 
• You have lean operations 
• Your overseas clients have long payment cycles 

Better for recurring exports

If exports happen frequently, avoiding repeated IGST payments can simplify operations significantly.

The LUT filing process is fully online and usually doesn’t take very long.

Step 1: Log in to the GST portal

Use your GST credentials to access the portal.

Step 2: Go to LUT filing section

Navigate to:

Services → User services → Furnish Letter of Undertaking (LUT)

Step 3: Select the financial year

Choose the relevant financial year for which you’re filing LUT.

Step 4: Fill form GST RFD-11

You’ll need to provide:

• Basic declarations 
• Witness details 
• Place of filing 

Step 5: Submit using DSC or EVC

Once submitted successfully, you’ll receive an ARN acknowledgement.

LUT is not permanent.

It is valid for only one financial year.

If you filed LUT for FY 2026-27, you’ll need to renew it again for the next financial year before continuing exports under LUT.

Missing renewal timelines can create unnecessary compliance complications later.

Some exporters also find:

• ITC refund filing more documentation-heavy.
• Refund processing slower in certain cases.
• Officer scrutiny more detailed.

So, while liquidity improves, compliance discipline becomes very important.

The IGST route works very differently from LUT.

Here, you export goods or services after paying IGST upfront. Later, you claim a refund for the tax you already paid.

So unlike LUT, where you avoid tax payment completely during export, the IGST route follows a “pay first, refund later” model.

For some exporters, this works well because the refund process can feel more automated, especially for goods exports linked with customs systems.

But the tradeoff is obvious:

Your money gets blocked temporarily until the refund is processed.

Here’s the typical flow:

Step 1: You raise export invoices with IGST.

Unlike LUT invoices, these invoices include IGST charges.

Step 2: You pay IGST.

This can happen through:

• Your ITC balance 
• Cash ledger 
• Or a combination of both 

Step 3: You file the shipping bill.

For goods exporters, the shipping bill becomes extremely important because it acts as the refund application in many cases.

Step 4: You file GSTR-1 and GSTR-3B.

The invoice details across returns and customs systems must match correctly.

Step 5: Refund gets processed.

If everything matches properly, the refund is processed through the customs/ICEGATE system.

Even though the upfront tax payment can affect liquidity, some exporters still choose this route because:

• Refund processing can feel more system-driven and relatively smooth when shipping bills, GST returns, and invoice data all match correctly.
• There may be less manual officer interaction. 
• Goods exporters often find customs-linked refunds operationally smoother.
• Businesses with large ITC balances may prefer utilizing them this way as part of their tax planning structure.

For example, a manufacturer exporting high volumes regularly may already have substantial ITC accumulation. In such cases, paying IGST through ITC and claiming a refund may fit their operational structure better.

The IGST route depends heavily on matching data.

A tiny mismatch between:

• Shipping bill 
• GST returns 
• Invoice numbers 
• Port codes 
• Tax values 

Can create reconciliation issues and slow down refunds significantly.

Even something as small as:

• “INV001” in one system 
• vs “INV-001” in another 

Another issue is that even if refunds are processed later, your money is still locked temporarily. For smaller exporters or startups, this can put pressure on them quickly.

With LUT, you export without paying IGST.

Otherwise, you pay IGST first and then claim a refund later.

But operationally, the differences go much deeper:

Working capital

The biggest difference is working capital. This is usually the deciding factor for most exporters.

With LUT:

• Your money stays with you.
• No upfront tax blockage.

With IGST:

• Money gets tied up temporarily.
• You wait for refunds to recover liquidity.

If your export cycle is large or recurring, this can become a serious cash flow consideration.

Compliance experience

The compliance experience also feels very different.

With LUT, you avoid upfront tax payment, but you usually handle:

• ITC refund applications.
• More documentation tracking.
• Export realization proof collection.
• Greater scrutiny during refund processing.

With IGST refunds, the process can feel more automated because it is linked with customs systems and shipping bills. But it also becomes heavily dependent on perfect data matching across returns and export filings.

Even small mismatches can delay refunds.

Refund dependency

Refund dependency differs too.

Under LUT, refunds are more dependent on:

• GST portal filings.
• ITC calculations.
• Supporting export documentation.

Under the IGST route, refunds depend more on:

• ICEGATE validation.
• Shipping bill accuracy.
• Customs reconciliation.
• GST return matching.

So while IGST may feel faster for some exporters, it can also become sensitive to invoice-level inconsistencies.

LUT vs IGST refund comparison

To make the differences easier to compare side-by-side, here’s a quick breakdown of how both routes work operationally:

The “better” route depends on:

• Your business model.
• Export frequency.
• Working capital situation.
• Documentation capability.
• Operational comfort with refund cycles.

Let’s break it down practically.

When LUT usually makes more sense

LUT is often preferred by:

• SaaS businesses 
• Freelancers 
• Agencies 
• IT service exporters 
• Consultants 
• Startups 

Why?

Because these businesses usually care a lot about liquidity and recurring cash flow.

If you’re receiving international payments every month, paying IGST first can create unnecessary financial pressure.

With LUT:

• You avoid blocking money.
• Your cash flow stays healthier.
• Operations feel lighter financially.

For many service exporters, this becomes the more comfortable option operationally.

When may the IGST refund route work better?

Some exporters still prefer the IGST route strategically. This is more common among:

• Manufacturers 
• Large goods exporters 
• Businesses with heavy ITC accumulation 

Why?

Because the customs-linked refund process may feel faster and more automated when everything matches correctly.

Instead of separately applying for ITC refunds under LUT, the refund process integrates more directly with export filings.

Filing LUT in Form GST RFD-11 is mostly an online process, so the documentation requirement is fairly minimal. In most cases, you’ll need:

• GST credentials/login access
• Details of two independent witnesses
• DSC or EVC for verification
• Previous LUT copy (if renewing)
• Basic business and export details

Some exporters may also keep supporting documents handy, such as:

• GST registration details
• IEC details
• Authorization letter or board resolution (if applicable)

The LUT is filed online through the GST portal under:

Services → User Services → Furnish Letter of Undertaking (LUT).

The legal basis for export refunds mainly comes from:

• Section 16 of the IGST Act: Defines zero-rated supplies and allows exporters to:
• Export under LUT without payment of IGST
• Export with IGST payment and claim refund later
• Rule 96A of the CGST Rules: Governs LUT/Bond filing for exports without payment of IGST
• Rule 89: Covers refund of unutilized ITC under the LUT route
• Rule 96: Covers refund of IGST paid on exports through the customs-linked mechanism

This happens more often than exporters expect. Usually, delays happen because of small inconsistencies.

Common LUT-related mistakes

• LUT not renewed on time.
• Export before LUT filing.
• Incorrect ITC calculations.
• Missing FIRA/FIRC documentation.

Common IGST refund mistakes

• Shipping bill mismatch.
• Invoice number mismatch.
• Wrong port code.
• Incorrect GST return reporting.

Documentation problems

Sometimes the issue isn’t GST itself. It’s export payment proof. Missing or delayed:

• FIRA 
• eFIRA 
• FIRC 
• BRC 

Can slow down compliance workflows and refund processing.

Exporters who usually experience smoother refunds tend to follow consistent, robust internal processes.

Reconcile everything regularly

Don’t wait until refund filing time. Match these every month if possible:

• GSTR-1
• GSTR-3B
• Shipping bills
• Invoice values
• Payment records

Standardize invoice formats

Small naming inconsistencies can create avoidable delays. Try keeping invoice structures uniform across:

• GST returns
• Accounting systems
• Customs filings

Keep export documentation organized

This includes:

• Contracts
• Invoices
• LUT copies
• FIRA/eFIRA
• Payment proof
• Bank records

The easier these are to access, the smoother compliance becomes.

Renew LUT early

Many exporters wait until the last moment. Filing LUT at the beginning of the financial year usually avoids unnecessary complications.

One of the biggest operational problems exporters face today is documentation fragmentation. You may receive payments successfully, but:

• FIRA retrieval takes time.
• Payment records stay scattered.
• Reconciliation becomes manual.
• Compliance tracking becomes stressful.

And when GST refund filing starts, finance teams often spend hours chasing paperwork.

Why does eFIRA matter for exporters?

For many exporters, especially service exporters, proof of export realization becomes important for:

• LUT compliance 
• GST refund processing 
• Audit readiness 
• Documentation verification 

Delays in obtaining these records can slow down workflows significantly.

How does Xflow simplify the process?

With Xflow’s auto eFIRA, exporters can access payment documentation more efficiently without relying heavily on manual follow-ups. This helps reduce:

• Documentation delays 
• Reconciliation effort 
• Operational friction 

Centralized payment visibility

Instead of tracking export payments across multiple systems manually, you get better visibility into:

• Incoming international payments
• Payment status
• Export transaction records
• Supporting documentation

This makes GST refund preparation easier.

Better LUT compliance readiness

Strong documentation becomes extremely important during:

• Refund scrutiny
• GST audits
• Compliance reviews

Automated eFIRA access helps maintain cleaner export records and stronger compliance readiness.

Especially useful for service exporters

If your business handles:

• Recurring overseas payments
• Multiple international clients
• High-volume export invoices

Manual documentation tracking can become messy quickly.

Automating these workflows can save significant operational time.

If your priority is keeping working capital free and avoiding upfront tax payments, LUT usually fits better. In case you are able to make IGST payments upfront and handle the refund process through customs, then the IGST method is perfect for your business.

However, at the end of the day, the decision will depend on how you export, how often you do shipping or invoicing, your financial position, and how easily you can handle the documentation and other processes.

One thing that will not be affected by all this is the fact that the refund process is always easier and faster with precise documentation.

That’s exactly where Xflow can help. It simplifies export payment tracking, automates eFIRA access, and keeps your export records organized, so your LUT compliance and GST refund process doesn’t slow down because of missing paperwork.

Want to see it in action for your export workflow? Signup Today and see how much smoother your refunds and compliance can be.