GST Reconciliation & ITC Matching: GSTR-2B, Mismatches & Compliance Guide

GST Reconciliation & ITC: Complete Guide to GSTR-2B, Mismatches and Input Tax Credit

For many businesses, GST compliance is treated as a monthly filing exercise:

Sales → GSTR-1 → GSTR-3B → Pay GST → Done.

But that approach can create a significant problem.

A business may have recorded ₹10 lakh of eligible purchases in its books, while the corresponding invoices appearing in GSTR-2B may be only ₹8.5 lakh.

Or the opposite may happen.

GSTR-2B may show an invoice that:

• was never recorded in the books,
• belongs to another GSTIN,
• has an incorrect value,
• has an incorrect GST amount,
• relates to an ineligible expense,
• has already been claimed,
• or requires reversal.

This is why GST reconciliation is not merely an accounting exercise.

It is an important control over:

• Input Tax Credit
• GST payable
• Working capital
• Vendor compliance
• GST return accuracy
• Audit readiness
• Tax risk

The GST Portal itself advises taxpayers to reconcile GSTR-2B with their own records and books, ensure that credit is not availed twice, reverse credit as required and ensure payment of reverse-charge tax. GST Tutorial

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What Is GST Reconciliation?

GST reconciliation is the process of comparing information from different GST and accounting records to identify differences and determine the correct amount of Input Tax Credit (ITC) that can be claimed.

A typical reconciliation compares:

Purchase Register

vs.

GSTR-2B

and may also involve:

GSTR-3B

GSTR-1

Vendor invoices

Books of accounts

Payment records

Credit/debit notes

E-invoice data

Import documents

The objective is not simply to make two reports match.

The objective is to determine:

What ITC is actually eligible to be claimed, what needs to be followed up with vendors, and what needs to be reversed or excluded?

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What Is Input Tax Credit?

Input Tax Credit allows an eligible registered person to claim credit for GST paid on eligible purchases and expenses used or intended to be used in the course or furtherance of business, subject to the conditions and restrictions under GST law.

Section 16 of the CGST Act sets out the basic eligibility framework. Among other conditions, the law requires prescribed documentation and contains additional conditions relating to supplier reporting and other requirements. CBIC GST

For a business, this means GST paid on eligible purchases does not necessarily become an ultimate cost.

Instead:

GST paid on eligible purchases

↓

Eligible ITC

↓

Set off against eligible output GST liability

This is one of the major reasons GST reconciliation matters.

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What Is GSTR-2B?

GSTR-2B is an auto-drafted Input Tax Credit statement generated for a registered taxpayer based on information furnished by suppliers and certain other sources.

The GST Portal describes GSTR-2B as a read-only, static ITC statement indicating the availability of ITC against documents furnished by suppliers/ISDs and certain import information. GST Tutorial

It includes information derived from sources such as:

• Supplier GSTR-1/1A/IFF
• GSTR-5
• GSTR-6
• Import data from ICEGATE

The GST Portal specifically states that GSTR-2B should be used to take the appropriate ITC in the relevant sections of GSTR-3B. GST Tutorial

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Is GSTR-2B the Same as Your Purchase Register?

No.

This distinction is extremely important.

Purchase Register

Your purchase register represents transactions recorded in your books/accounting system.

GSTR-2B

GSTR-2B represents information available in the GST system based on supplier/other reporting.

Therefore:

Your purchase register and GSTR-2B are two different data sources.

Reconciliation is the process of understanding the differences between them.

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Simple Example

Suppose ABC Pvt Ltd's books show:

But GSTR-2B shows:

Eligible ITC = ₹8,20,000

Difference:

₹80,000

The business should not simply claim the ₹9 lakh recorded in its books.

It needs to investigate the ₹80,000 difference.

Possible reasons could include:

• Supplier hasn't filed/declared invoice
• Wrong GSTIN
• Invoice amendment
• Timing difference
• Credit note
• Ineligible ITC
• Duplicate booking
• Data-entry error
• Import-related differences
• Other reconciliation issues

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Why GST Reconciliation Is Important

1. Prevents Excess ITC Claims

Claiming ITC that is not eligible can create tax exposure.

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2. Identifies Missing ITC

Reconciliation can also work in the opposite direction.

Suppose your books show:

₹10 lakh GST

but GSTR-2B shows:

₹8 lakh

The missing ₹2 lakh should not simply be written off.

You may need to determine whether:

• vendors have not reported invoices,
• invoices were reported in another period,
• GSTIN details are incorrect,
• invoices were amended,
• or the underlying purchase itself needs review.

This can help recover legitimate credit where permitted.

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3. Detects Vendor Compliance Problems

Your business may have paid the supplier and recorded the invoice correctly.

But if the supplier fails to report the invoice correctly, the ITC position can be affected.

This makes GST reconciliation a useful vendor-compliance control, not merely an accounting function.

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4. Prevents Duplicate ITC

The GST Portal specifically advises taxpayers to ensure that:

no credit is availed twice for any document. GST Tutorial

Duplicate ITC can arise from:

• duplicate invoice entries,
• amendments,
• manual and automated imports,
• credit-note treatment,
• accounting-system errors,
• multiple GST registrations.

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5. Improves Working Capital

Correct ITC directly affects GST cash outflow.

Suppose:

Output GST = ₹15 lakh

Eligible ITC:

₹9 lakh

Net tax payable:

₹6 lakh

If the business fails to identify ₹2 lakh of eligible ITC because of poor reconciliation, the cash outflow could increase unnecessarily.

Therefore:

GST reconciliation can become a working-capital control.

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GSTR-2B vs GSTR-3B vs Books

No single report should automatically be treated as the complete answer.

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What Does a GST Reconciliation Actually Match?

A good reconciliation doesn't only compare total GST amounts.

At invoice level, businesses should ideally compare fields such as:

The more granular the reconciliation, the easier it becomes to identify the root cause of differences.

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The 5 Major Types of GST Reconciliation Differences

A practical reconciliation can classify differences into five major categories.

1. Matched

Invoice exists in both books and GSTR-2B.

Action: Generally proceed subject to eligibility review.

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2. Books Not in GSTR-2B

Invoice exists in your purchase register but is absent from GSTR-2B.

Possible reasons:

• Supplier has not filed the invoice
• Supplier filed late
• Incorrect GSTIN
• Invoice reported in another period
• Supplier amended the invoice
• Data-entry issue

Action: Investigate and follow up.

---

3. GSTR-2B Not in Books

Invoice appears in GSTR-2B but is not recorded in your books.

Possible reasons:

• Invoice was missed
• Purchase was booked in another ledger
• Duplicate supplier record
• Wrong GSTIN
• Expense belongs to another entity
• Unrecorded liability

Action: Verify the underlying invoice before taking any accounting or ITC action.

---

4. Amount Mismatch

Invoice exists in both records but values differ.

Example:

Books:

Taxable value = ₹1,00,000

GSTR-2B:

Taxable value = ₹90,000

Possible reasons:

• Supplier amendment
• Credit note
• Partial booking
• Accounting error
• Taxable-value difference

---

5. Eligibility Difference

The invoice exists in GSTR-2B and books, but ITC may still not be available.

This is one of the most important concepts.

Presence in GSTR-2B does not automatically mean that every rupee of ITC is eligible.

The GST Portal itself cautions that there can be situations where ITC is not available even though the system-generated statement does not identify every possible ineligibility scenario. Taxpayers are expected to self-assess and reverse such credit where required. GST Tutorial

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GSTR-2B Does Not Replace Your Own ITC Review

This is worth highlighting.

The GST Portal explains that only certain scenarios are specifically marked as "ITC Not Available" in GSTR-2B.

There can be other situations under GST law where ITC may not be available, and taxpayers must self-assess those cases. GST Tutorial

Therefore:

Wrong approach

GSTR-2B shows ITC → claim everything

Better approach

GSTR-2B → reconcile → verify eligibility → claim appropriate ITC

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Section 16 Conditions for ITC

Section 16 of the CGST Act contains important conditions governing ITC.

These include requirements relating to documentation and supplier reporting, along with other conditions prescribed under GST law. CBIC GST

The broad practical checklist should therefore include:

☐ Valid tax invoice/debit note or prescribed document

☐ Correct GSTIN

☐ Supply actually received

☐ Business use

☐ Supplier reporting requirements satisfied

☐ Applicable tax has been properly accounted for

☐ No duplicate ITC

☐ No blocked/ineligible credit

☐ Applicable payment/reversal requirements considered

☐ ITC claimed within the applicable statutory time limit

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What Are Blocked Credits?

Section 17(5) of the CGST Act specifies categories of supplies for which ITC is restricted or unavailable, subject to the statutory exceptions.

Examples include certain:

• Motor vehicles/conveyances
• Food and beverages
• Club memberships
• Certain insurance
• Certain personal-consumption expenditure

The precise applicability depends on the facts and statutory exceptions. CBIC GST

Therefore, a reconciliation should not stop at:

"Invoice found in GSTR-2B."

It should also ask:

"Is this ITC legally eligible?"

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Example: GSTR-2B Shows ITC but It Is Not Automatically Claimable

Suppose a company sees:

₹25,000 GST

in GSTR-2B relating to an expense.

The accounting team claims the ₹25,000.

But on review, the expense falls within a category where ITC is blocked under Section 17(5), and no exception applies.

The issue is not a reconciliation mismatch.

It is an ITC eligibility issue.

This is why good GST reconciliation has two separate layers:

Layer 1

Data reconciliation

Does the invoice match?

Layer 2

Eligibility review

Is the ITC legally claimable?

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What Happens When a Supplier Has Not Uploaded the Invoice?

Suppose:

You purchased goods in June.

Invoice value:

₹5,00,000 + ₹90,000 GST

Your books contain the invoice.

But the supplier has not correctly reported it.

Therefore, the invoice may not appear in the relevant GSTR-2B.

The correct response is not simply:

"Claim it anyway because I have the invoice."

The taxpayer should evaluate the applicable ITC conditions and determine the appropriate treatment.

At the operational level, this should also trigger vendor follow-up.

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Vendor Follow-Up Should Be Part of GST Reconciliation

A mature GST process should not end with:

"Mismatch found."

It should continue to:

Mismatch identified

↓

Vendor identified

↓

Reason communicated

↓

Vendor correction requested

↓

Correction monitored

↓

Next GSTR-2B checked

↓

ITC action taken

This converts reconciliation from a reporting exercise into a control system.

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What Is IMS and Why Does It Matter?

The GST Portal's Invoice Management System (IMS) allows recipients to take actions on invoices/records saved or filed by suppliers through GSTR-1/1A/IFF, including accepting, rejecting or keeping records pending for ITC-related processing. GST Tutorial

IMS was introduced as an additional mechanism to help recipients manage invoice information before ITC is ultimately reflected through the GST return process.

Therefore, businesses should incorporate IMS into their GST control framework where applicable.

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GSTR-2B Is Static

One important feature of GSTR-2B is that it is a static statement for the relevant period.

The GST Portal states that taxpayers cannot directly modify or add documents to GSTR-2B. GST Tutorial

If a supplier subsequently files information that falls into a later GSTR-2B period, the document can appear in that later statement based on the applicable cut-off.

This is one reason why reconciliation can require period-over-period tracking.

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Timing Differences Are Normal

Not every mismatch means something is wrong.

Example:

Invoice date:

30 June

Supplier files the invoice in a later period.

The document may therefore appear in a subsequent GSTR-2B rather than the period you initially expected.

The GST Portal explains that documents furnished by suppliers after the applicable cut-off can flow into the next open GSTR-2B. GST Tutorial

Therefore:

A good reconciliation system should distinguish timing differences from genuine errors.

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How to Reconcile GST Step-by-Step

Step 1 — Close the purchase register

Ensure the accounting team has recorded all relevant purchase invoices for the period.

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Step 2 — Download GSTR-2B

Download the relevant period's GSTR-2B from the GST portal.

The GST Portal allows GSTR-2B to be viewed and downloaded, including in Excel/JSON formats. GST Tutorial

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Step 3 — Standardise the data

Normalise:

• GSTIN
• Invoice number
• Invoice date
• Taxable value
• IGST
• CGST
• SGST
• Cess

This is especially important when data comes from different systems.

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Step 4 — Match invoices

Match:

GSTIN + invoice number + invoice date + taxable value + tax

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Step 5 — Categorise differences

Create categories such as:

• Matched
• Books not in 2B
• 2B not in books
• Value mismatch
• GST mismatch
• Duplicate
• Credit note
• Ineligible
• Timing difference
• Vendor correction required

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Step 6 — Perform eligibility review

Review:

• Business purpose
• Documentation
• Blocked credit
• Receipt of supply
• Other Section 16 conditions
• Reversal requirements

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Step 7 — Follow up with vendors

Create a vendor-wise exception report.

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Step 8 — Track unresolved items

Don't simply close the monthly reconciliation file.

Carry unresolved invoices into the next period.

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Step 9 — Reconcile with GSTR-3B

Compare:

Eligible ITC identified

vs.

ITC actually claimed

The difference should be explainable.

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Step 10 — Maintain an audit trail

Keep:

• Reconciliation file
• Exception report
• Vendor communication
• Supporting invoices
• Management approvals
• Reversal/reclaim workings
• Final GSTR-3B

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Sample GST Reconciliation Format

A business can maintain a reconciliation file like this:

This type of file creates a clear audit trail.

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How Businesses Can Reduce GST Mismatches

GST reconciliation should not be treated only as a month-end exercise.

Businesses can reduce mismatches by improving the underlying process.

1. Capture GSTIN correctly

A wrong GSTIN can create reconciliation problems from the beginning.

2. Standardise vendor onboarding

Collect and validate:

• Legal name
• GSTIN
• State
• Billing details
• E-invoice applicability

3. Control invoice booking

Avoid duplicate invoices and incorrect tax coding.

4. Communicate vendor requirements

Tell suppliers what information must appear correctly on invoices.

5. Monitor vendor filing behaviour

Repeated missing invoices can indicate a vendor-compliance problem.

6. Reconcile monthly

Don't wait until the annual return.

7. Maintain exception ageing

Track unresolved invoices for:

• 0–30 days
• 31–60 days
• 61–90 days
• 90+ days

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GST Reconciliation Dashboard

For larger businesses, management should ideally see a monthly dashboard.

Example:

Total ITC as per Books

₹52.4 lakh

ITC appearing in GSTR-2B

₹49.8 lakh

Matched

₹47.9 lakh

Missing in 2B

₹2.6 lakh

2B not in Books

₹1.9 lakh

Potentially ineligible

₹0.7 lakh

Vendor corrections pending

₹1.4 lakh

Duplicate/other exceptions

₹0.3 lakh

This turns GST reconciliation into a management information system, not merely a compliance spreadsheet.

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What Management Should Monitor

A GST dashboard can track:

ITC metrics

• ITC as per books
• ITC as per 2B
• ITC claimed
• ITC reversed
• ITC pending
• ITC mismatch %

Vendor metrics

• Vendors with missing invoices
• Repeat non-compliant vendors
• Pending corrections
• Average resolution time

Compliance metrics

• GSTR-1 filed on time
• GSTR-3B filed on time
• IMS actions pending
• ITC reversals
• RCM liabilities
• E-invoice exceptions

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GST Reconciliation for Different Types of Businesses

Manufacturing

Reconciliation may involve:

• Raw materials
• Consumables
• Capital goods
• Job work
• Freight
• Vendor invoices
• Imports

The volume can make automated reconciliation particularly valuable.

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E-commerce

Potential issues include:

• High invoice volume
• Multiple GST registrations
• Marketplace transactions
• TCS
• Returns
• Credit notes
• Vendor reconciliation

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SaaS / IT Companies

Common areas include:

• Software subscriptions
• Professional services
• Employee-related expenses
• Foreign services
• RCM
• Multiple states

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Construction Businesses

Reconciliation can become more complex due to:

• Contractors
• Subcontractors
• Materials
• Capital expenditure
• Retention amounts
• Credit/debit notes
• Multiple project locations

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Professional Services Firms

Typical areas include:

• Rent
• Software
• Professional fees
• Advertising
• Travel
• Office expenses
• Outsourced services

The eligibility of ITC should always be assessed under the applicable GST provisions rather than assuming every business expense carries eligible credit.

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GST Reconciliation vs GST Return Filing

These are not the same service.

GST Return Filing

Primarily involves preparing and filing the applicable GST returns.

GST Reconciliation

Involves:

• Comparing records
• Identifying mismatches
• Reviewing ITC
• Following up with vendors
• Tracking corrections
• Reviewing reversals
• Maintaining an exception trail

A business can have its GST returns filed every month and still have a weak GST reconciliation process.

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What Happens If ITC Is Claimed Incorrectly?

Incorrect ITC can result in:

• Reversal of credit
• Additional tax liability
• Interest
• Penalties or other consequences depending on the nature of the issue and applicable law
• Increased scrutiny
• Reconciliation problems during audit or assessment

Therefore:

"ITC available in 2B" and "ITC legally claimable" should never be treated as identical concepts.

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How Taxomic Can Help With GST Reconciliation

For businesses that don't have a dedicated GST/accounting team, Taxomic can structure the process around four layers:

1. Data

Collect:

• Purchase register
• GSTR-2B
• GSTR-3B
• Vendor data
• Invoices

2. Reconciliation

Identify:

• Matched invoices
• Missing invoices
• Duplicates
• Mismatches
• Timing differences

3. Compliance Review

Review:

• ITC eligibility
• Reversals
• RCM
• Blocked credits
• Documentation

4. Exception Closure

Track:

• Vendor follow-ups
• Corrections
• Reconciliation status
• Pending items
• Management reporting

The goal is not simply to file GST returns.

The goal is to create a GST process where management knows:

How much ITC is available, how much is claimable, what is missing, what is at risk and what needs action.

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GST Reconciliation Checklist

Before finalising your GST return, check:

Purchase data

☐ Purchase register closed

☐ All invoices booked

☐ GSTIN validated

☐ Duplicate invoices removed

GSTR-2B

☐ GSTR-2B downloaded

☐ Invoice-level reconciliation completed

☐ Missing invoices identified

☐ Excess invoices identified

☐ Credit/debit notes reviewed

ITC eligibility

☐ Business-use test considered

☐ Required documents available

☐ Receipt of supply considered

☐ Blocked credits reviewed

☐ Reversal requirements reviewed

☐ RCM considered

Vendor management

☐ Missing invoices communicated

☐ Vendor corrections tracked

☐ Repeat vendor issues identified

Return

☐ Eligible ITC reconciled with GSTR-3B

☐ ITC reversals recorded

☐ RCM liability considered

☐ Final return reviewed

☐ Reconciliation file archived

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Frequently Asked Questions

What is GST reconciliation?

GST reconciliation is the process of comparing purchase/accounting records with GST data such as GSTR-2B and identifying differences before determining the appropriate ITC to claim.

Is GSTR-2B mandatory to reconcile?

The GST Portal advises taxpayers to reconcile GSTR-2B with their own records and books and to ensure that ITC is not claimed twice and required reversals are made. GST Tutorial

Can I claim all ITC appearing in GSTR-2B?

No. GSTR-2B is an important source for ITC availability, but taxpayers must still self-assess eligibility under GST law. The GST Portal specifically warns that there may be other situations where ITC is not available that are not fully identified by the system. GST Tutorial

What if an invoice is in my books but not in GSTR-2B?

Investigate the reason. It could be a supplier filing/timing issue, incorrect GSTIN, amendment or another discrepancy. The invoice should be tracked and treated according to the applicable ITC provisions.

What if GSTR-2B contains an invoice that isn't in my books?

Verify the invoice and supplier before taking any accounting or ITC action. It could be a missed purchase, incorrect reporting or another issue.

Can GSTR-2B be edited?

No. GSTR-2B is a read-only statement. Taxpayers cannot directly add or modify documents in it. GST Tutorial

How often should GST reconciliation be done?

For most active businesses, monthly reconciliation is the stronger control because it allows discrepancies and vendor issues to be identified closer to the transaction period.

What is the difference between GSTR-2A and GSTR-2B?

GSTR-2B is a static, system-generated ITC statement for the relevant period. GSTR-2A is a dynamic statement that changes as suppliers upload or amend information. Businesses should understand the specific role of each report within their GST process.

Can GST reconciliation be automated?

Yes. For businesses with significant invoice volumes, reconciliation can be supported through accounting software, spreadsheets, APIs or specialised GST reconciliation tools. However, automation should not replace the underlying eligibility review.

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Final Takeaway

GST reconciliation should not be viewed as:

"Does my purchase register equal GSTR-2B?"

The real question is:

"Have we correctly identified the ITC that is available, eligible, properly documented and appropriate to claim in our GST return?"

A strong GST process therefore looks like:

Books

↓

GSTR-2B

↓

Invoice-level reconciliation

↓

Eligibility review

↓

Vendor follow-up

↓

Reversal / correction / reclaim where appropriate

↓

GSTR-3B

↓

Management review

This approach can reduce GST errors, improve working-capital visibility and create a much stronger audit trail.

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Need GST Reconciliation & Accounting Support?

Taxomic provides GST accounting, reconciliation and compliance support for businesses in Bangalore and across India.

We can help businesses with:

• GST return filing
• GSTR-2B reconciliation
• ITC reconciliation
• Vendor reconciliation
• GST accounting
• GST compliance review
• GST notice support
• Monthly accounting and MIS

Get a GST Compliance Assessment

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