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GST min readUpdated 2026-04-20

GST Reconciliation Guide: GSTR-2A vs 2B vs Purchase Register (Step-by-Step)

A practical guide to monthly GST reconciliation — understanding GSTR-2A vs GSTR-2B, how to match ITC with your purchase register, handling supplier mismatches, and staying ITC-safe.

GSTR-2A vs GSTR-2B: The Critical Difference

GSTR-2A is a dynamic, real-time document that shows purchases uploaded by your suppliers in GSTR-1. It keeps updating as suppliers file or amend returns. GSTR-2B is a static, locked document generated on the 14th of each month showing ITC available for that month — based on GSTR-1/IFF filed by suppliers up to 13th. Rule 36(4) now mandates that ITC can only be claimed up to the amount appearing in GSTR-2B (plus a 5% buffer that was later removed). Always use GSTR-2B as the basis for ITC claims in GSTR-3B.

FeatureGSTR-2AGSTR-2B
NatureDynamic, keeps updatingStatic, locked by 14th
UseVerification and trackingITC claim basis in GSTR-3B
Update timingReal-time as suppliers fileFixed on 14th of each month
Legal standingInformationalLegally determinative for ITC

Step-by-Step Monthly ITC Reconciliation Process

Follow this process every month before filing GSTR-3B:

  • Download GSTR-2B from GST portal for the month
  • Export your purchase register from accounting software for the same period
  • Match each invoice line: GSTIN, invoice number, invoice date, taxable value, IGST/CGST/SGST
  • Identify mismatches: invoices in your books but not in 2B, or in 2B but not in your books
  • For invoices in books not in 2B: check if supplier filed GSTR-1, follow up with supplier
  • For invoices in 2B not in your books: verify if purchase was made and book if genuine
  • Claim ITC only for matched invoices in GSTR-3B
  • Document the reconciliation for audit trail

Common Reconciliation Mismatches and How to Handle

Understanding what causes mismatches helps you fix them systematically.

Mismatch TypeCauseAction Required
Invoice in books, not in 2BSupplier hasn't filed GSTR-1 yetFollow up with supplier to file GSTR-1
Invoice in 2B, not in booksPurchase recorded in wrong month or not yet recordedBook the purchase; verify it's a genuine purchase
Invoice in both but amount differsData entry error in your books or supplier filed wrong valueVerify original invoice; ask supplier to amend if their filing is wrong
GSTIN mismatchWrong GSTIN on invoiceAsk supplier to issue corrected invoice
Invoice dated in previous period appearing nowSupplier filed lateCan claim ITC in current month — check if invoice within 3-year ITC eligibility window

ITC Reversal Rules You Must Know

Not all ITC in GSTR-2B can be claimed. ITC must be reversed for: (1) Input used for exempt supplies — Rule 42 (proportionate reversal), (2) Personal use or non-business use, (3) Payment not made to supplier within 180 days — must reverse ITC and add back when payment is made, (4) Blocked credits under Section 17(5) — motor vehicles, food, club membership, etc., (5) Capital goods used for exempt supply — Rule 43 reversal.

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