GST Reconciliation Do’s and Don’ts: Why a Green Match Rate Is Not Enough

A high match percentage does not prove that input tax credit is correct. The meaningful question is whether the residual population is classified, owned and supported—and whether the amount claimed in GSTR-3B ties back to the books and the source statements.

Do preserve the source populations

Keep the original purchase register, GSTR-2B snapshot, GSTR-3B filed return and any later amended extracts. Record the download date and period. Keep pre-clean counts so a reviewer can see whether rows disappeared during normalisation.

Do split the exception reasons

Use separate buckets for:

• books-to-2B timing difference;
• supplier has not filed or has amended later;
• GSTIN, invoice number or tax amount mismatch;
• duplicate in books or duplicate credit;
• credit note not linked;
• blocked or ineligible ITC;
• reverse charge, import or branch-treatment question;
• credit deferred or reversed in a later period;
• manual review required.

“Mismatch” is not a conclusion. It is only the first label in the investigation.

Don’t use fuzzy matching as proof

AI can normalise punctuation, identify likely invoice pairs and draft follow-up emails. It should not override a materially different GSTIN, invoice number or tax amount. Exact controls should run first; fuzzy matches should be low-confidence review candidates with a visible reason and threshold.

Don’t combine eligibility and matching

An invoice may match GSTR-2B and still require an eligibility review. Conversely, a timing difference may be fully explainable without becoming a permanent exception. Keep the match result, eligibility result, action, owner and closure evidence as separate fields.

The five-minute manager review

Before the file is closed, ask:

1. Does the final ITC claim tie to GSTR-3B and the ledger?
2. Are all high-value unmatched rows assigned to an owner?
3. Are blocked credits and reversals separately identified?
4. Are credit/debit notes and amendments linked to the original invoice?
5. Can another reviewer reproduce the population and the decision?

Use the GST 2B reconciliation checker, Clause 44 working paper and GST reconciliation workflow as the operating set. AI should shrink the investigation queue, not manufacture a green dashboard.

The GST Portal’s GSTR-2B FAQ describes 2B as a read-only, static, auto-drafted ITC statement and advises reconciliation with the taxpayer’s books. Check the live portal guidance for period-specific changes before relying on a rule or due date.

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