A GSTR-2B mismatch should be split into categories before GSTR-3B is filed. Match the purchase register to the relevant 2B at invoice level, then separate missing supplier invoices, duplicates, wrong GSTINs, value/tax differences, credit notes, timing items, blocked or ineligible ITC and IMS actions. The objective is not to force both totals to match—it is to explain every material difference.
A good ITC reconciliation is an action list
The output should say which invoices can be considered, which need supplier action, which are ineligible and which are timing differences.
Any regular taxpayer claiming material ITC
It is especially useful where invoice volume is high, suppliers file late or the business has several branches/cost centres.
Commercial posting and supplier GST reporting are independent
Your AP team can book an invoice correctly while the supplier reports it incorrectly or later.
The eight mismatch buckets
Missing invoice, duplicate, wrong GSTIN, value/tax difference, credit note, timing, ineligible/blocked ITC and IMS action.
| Bucket | Example | Owner/action |
|---|---|---|
| Missing in 2B | Supplier omitted invoice | Supplier follow-up |
| Wrong GSTIN | Invoice reported to another GSTIN | Supplier amendment |
| Value difference | Taxable value mismatch | Invoice/amendment check |
| Credit note | Supplier reduced tax | Book and ITC adjustment |
| Timing | Appears in later period | Track to later 2B |
| Ineligible | Blocked/personal/non-business | Exclude/reverse |
| IMS pending/rejected | Recipient action unresolved | Review before final ITC |
Download → standardise → match → bucket → assign → approve
Use a stable invoice key, retain both matched and unmatched reports, and avoid deleting differences merely to make totals agree.
1,200 invoices, ₹4.6 lakh unmatched ITC
After matching, ₹2 lakh is timing, ₹1.1 lakh wrong GSTIN, ₹80,000 credit notes, ₹40,000 duplicate and ₹30,000 blocked credit. The filing decision should differ by bucket.
Supplier issues surface only after deadlines or notices
A monthly ₹20,000 problem becomes a ₹2.4 lakh annual backlog with weaker supplier evidence.
Every unmatched invoice gets a next owner
We review register quality, 2B, IMS, supplier status, invoice evidence, eligibility, section 16 timing and prior reversal/reclaim history.
What TargoLegal would ask for before filing or responding
The exact pack changes by issue, but these controls prevent the most common hand-off and accountability failures.
The proposed filing, payment, reversal, correction or response should be explained before submission. After filing, retain the ARN/filed PDF and any acknowledgement.
Do not make the problem harder to unwind
Reconcile books and source evidence before deciding tax treatment.
Use the exact period that created the mismatch, notice or filing obligation.
A correction should have a written bridge to the original error.
Save return PDFs, ARN, challans and the approved working.
What to send for a first review
Want to reconcile 2B before filing? Send the tax month and approximate purchase-invoice volume so the matching and exception workflow can be scoped.
Related questions
What should I send first?
Send the GSTIN, exact tax period and the document or mismatch that triggered the question. That usually determines the rest of the checklist.
Should I pay before reconciling?
Do not make a blind payment merely because a portal difference appears. Establish the legal and factual basis first, unless an undisputed liability is already clear.
Can the GST Portal data be wrong or incomplete?
Portal data is essential evidence but it still has to be reconciled with books, supplier/customer records and the applicable law.
What should I keep after filing?
Retain the filed return PDF, ARN, payment evidence, reconciliation working and any client-approved summary of adjustments.
When should I involve a GST professional?
Professional review is advisable where the issue affects material tax, ITC, notices, refund, registration status, exports, e-invoicing or multiple return periods.
Official sources used
Legal and portal claims on this page were anchored to the official sources below. Secondary discussions are not used as legal authority.
TargoLegal Research and Editorial Desk · Last legally reviewed: 18 August 2026. GST Portal workflows, notifications and due-date extensions should be rechecked immediately before action.
