Reconciling GSTR-2B in TallyPrime. Where the Alt+O workflow stops

TallyPrime will pull your GSTR-2B in, line it up against your purchase vouchers, and sort most of it into tidy buckets on its own. That is the easy majority of the register. The remaining invoices are the ones an auditor actually asks about, and no button in Tally resolves them — someone still has to open the phone and call the vendor.

What the Alt+O workflow actually does

TallyPrime's GSTR-2B reconciliation is a comparison engine, not a filing tool. You are not filing anything from Tally — you are pulling the GST portal's statement of what your suppliers reported against your GSTIN, and lining it up against the purchase vouchers already sitting in your books, invoice by invoice. Tally auto-matches on the party GSTIN, document number and date, and the taxable and tax amounts, marks what agrees, and sorts what doesn't into named categories so a human can work through them in order rather than eyeballing two spreadsheets. (Tally does not publish its full matching logic; what its help documentation does specify is how a "potential match" is defined — see below.)

That is a real time saving on the bulk of a typical purchase register that matches cleanly. It is also the limit of what the report does. It tells you where books and portal disagree. It does not tell you why a supplier hasn't filed, and it does not track what happens to an invoice after it passes the 2B check — that is a separate legal test, covered further down.

The setup, step by step

Two ways to get GSTR-2B into Tally, and the reconciliation report that reads it:

Do step 7 as a habit, not an exception. The next section explains why.

Reading the Reconciliation Statistics report

Tally's summary view sorts every invoice into one of nine named buckets. Here's what each one is actually telling you:

Inside Unreconciled and Mismatched, F12 can also surface "potential matches" — near-hits Tally thinks are the same invoice despite a difference, split out as excluding-doc-no, excluding-GSTIN or excluding-section. A common real case: your books carry MC/233 and the portal carries MC/2333 — same supplier, same date, same amount, one digit off. Tally surfaces that as a potential match; Alt+W copies the portal's document number onto your voucher once you've confirmed by eye that it's the same invoice.

Where the report stops, and a human has to start

Not every bucket above resolves with a keystroke. Three categories specifically need someone to go and ask the vendor a question, and Tally has no mechanism for that conversation:

• Available Only on Portal. A supplier has reported an invoice against your GSTIN that isn't in your purchase register at all. That could be a genuine purchase your books missed — or it could be someone else's transaction mis-keyed against your GSTIN. Either way, someone has to call the vendor and find out which, before deciding whether to book it or dispute it.
• Available Only in Books, unmatched after two cycles. A purchase you've recorded that the supplier still hasn't reported. This is the invoice that turns into a vendor-not-filed problem — the fix isn't in Tally, it's a conversation with accounts payable at the vendor's end, and the earlier you start it, the more runway you have before Rule 37A's deadline.
• Invoices Rejected in IMS. Tally shows you rejected the record, but it doesn't tell you why you rejected it three weeks ago, or whether the vendor has since corrected and re-filed it. Someone has to go back to the source.

Multiply that across a purchase register with a few hundred vendors, and going bucket by bucket, vendor by vendor, chasing each one down by phone or email is exactly the part that is painful to do manually — Tally sorts the exceptions correctly; it doesn't have a vendor's phone number.

What a "Reconciled" invoice still doesn't tell you

Matching in Tally's GSTR-2B report answers one question: does this invoice appear in 2B the way you've booked it. That's the precondition for the credit under Section 16(2)(aa) of the CGST Act read with Rule 36(4)(b) of the CGST Rules — the invoice must be furnished by the supplier in GSTR-1 and the credit communicated to you in GSTR-2B, and the register is the answer to "is it in books but not in 2B", not "is it safe to keep". Two separate rules can still claw the credit back after a clean match, and Tally's 2B reconciliation report is not built to track either one:

Both are reasons an invoice that reconciled cleanly this month can still owe a reversal later — one on your payment discipline, one on your supplier's filing discipline, and re-availment on Rule 37A is triggered by the supplier filing that return, not by them actually paying the tax. Neither shows up by opening the GSTR-2B Reconciliation report a second time; they need their own ageing, tracked against invoice date and supplier filing status respectively, not against the 2B statement.

Three things that break, and the fix

Invoice number format mismatches that never resolve on their own

A recurring friction reported by Tally users across releases is a formatting gap between the number in your voucher and the number the supplier typed into their GSTR-1 — a missing slash, a leading zero, "GST/24-25/001" versus "001". Tally's potential-match view catches the obvious ones; anything with two differences at once (a digit and a separator) may sit in Unreconciled indefinitely unless someone opens both sides and compares by eye.

Recompute forgotten after a late IMS decision

Because GSTR-2B changes when you act on it in IMS after the 14th, a reconciliation you ran early in the month can go stale without any error message. If a filing deadline is close, re-run Recompute GSTR-2B as the last step before you touch the return, not the first.

Multiple GSTINs in one Tally company

If you reconcile across branches or states under one Tally company, F3 lets you switch the GST registration the report is built against. Reconciling the wrong GSTIN's 2B against a different branch's purchase vouchers produces a report that looks complete and is comparing the wrong data entirely — check F3 before you trust a "Reconciled" count.

What Recoup does once Tally has sorted the easy majority

Recoup takes the same Tally purchase register export and the same GSTR-2B and does the invoice-level match, but it carries the exceptions further than the portal-vs-books comparison: it names the specific vendor behind each unmatched invoice, tracks the Rule 37 180-day clock per invoice against your actual payment dates, and flags credits exposed to Rule 37A reversal by watching supplier GSTR-3B filing status directly — the two questions the Reconciliation Statistics report cannot answer because they were never inside its scope. Tally tells you what doesn't match. Recoup is built to tell you who to call, and when the clock on that invoice actually runs out.

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