GSTR-2B reconciliation: the complete guide

Input tax credit is real money — often the difference between a thin month and a fine one. And it is the single easiest thing for a growing business to lose, because losing it requires no mistake on your part at all. A supplier files late, or types your GSTIN wrong, and your credit quietly does not exist.

GSTR-2B reconciliation is how you find that out in time to do something about it.

What GSTR-2B is, and why it’s the one that binds

GSTR-2B is an auto-drafted statement generated for you each month, listing the input tax credit available based on what your suppliers actually filed. The critical property is that it is fixed for the period: generated on the 14th of the following month, changed only if you recompute it after acting in the Invoice Management System, and final once your GSTR-3B is filed.

That matters because reconciliation needs a fixed target. You cannot meaningfully tie out to a document that changes underneath you.

GSTR-2A vs GSTR-2B

	GSTR-2A	GSTR-2B
Nature	Dynamic — keeps updating	Fixed for the period; recomputed only on your IMS actions
Late supplier filings	Appear in the original period	Appear in the period of filing
Same query, two days apart	Can differ	Identical, unless you recompute it
Use it for	Tracing history	Monthly reconciliation and claiming

Businesses that reconcile against 2A end up re-doing the same month repeatedly and never quite closing it. Use 2B.

Where the Invoice Management System fits

Since October 2024, GSTR-2B is no longer simply whatever your suppliers filed. Every invoice, debit note and credit note they report lands first in the Invoice Management System (IMS) on the GST portal, where you decide what happens to it:

Your action	What happens
Accept	The record goes into your GSTR-2B and the credit is available to you.
Reject	It stays out of your GSTR-2B. Use it for invoices that aren’t yours or are wrong.
Pending	It stays out of this month’s 2B and carries forward. Credit notes and downward amendments can only be kept pending for one tax period.
No action	Treated as accepted, and included in 2B automatically.

Two consequences matter for the reconciliation. First, doing nothing is a decision: an invoice you never looked at is deemed accepted, including a wrong one. Second, if you change your mind after the 14th, you have to recompute GSTR-2B from the IMS dashboard before filing GSTR-3B, or the return will be built on the old version.

In practice IMS moves the work earlier in the month. The reconciliation below is what tells you which records to accept, reject or hold, so run it against IMS as suppliers report, not just against the finished 2B.

The reconciliation, step by step

Step 1 — Get both sides into the same shape

Download the 2B for the period. Export your purchase register for the same period. Then normalise, because this is where most reconciliations silently fail:

• Upper-case every GSTIN and strip spaces
• Standardise invoice numbers — leading zeros, slashes and prefixes are the usual culprits
• Standardise dates to one format
• Round tax amounts consistently, to two decimals on both sides

Step 2 — Match on four fields, not one

Match on GSTIN + invoice number + taxable value + tax amount. Matching on amount alone produces false pairs — two invoices from the same supplier for the same value in the same month is common, and pairing them wrongly hides a genuine gap while inventing a fake one.

Step 3 — Classify what didn’t match

Every unmatched line falls into one of the seven types below. Classification is the whole job: each type has a different owner and a different action.

Step 4 — Act before you file

Chase suppliers, correct your own entries, and decide consciously on anything you cannot resolve — claim it, or defer it. What you must not do is file GSTR-3B without having made that decision explicitly.

The seven mismatch types

Type	What it means	Action
In books, not in 2B	Supplier hasn’t filed, filed late, or used a wrong GSTIN	Chase supplier immediately. Consider deferring the claim.
In 2B, not in books	Invoice never recorded, or recorded in another period	Find the missing purchase entry — often an unbooked expense
Value mismatch	Taxable value differs between the two	Compare against the physical invoice; one side is wrong
Tax head mismatch	You booked IGST, supplier reported CGST/SGST (or the reverse)	Place of supply was wrong somewhere. Needs correcting, not netting.
Wrong GSTIN	Supplier reported against a different registration of yours	Common in multi-state businesses. Supplier must amend.
Period mismatch	Same invoice, different month on each side	Usually a cut-off issue. Note it and carry forward.
Ineligible credit	Appears in 2B but blocked or not eligible for you	Do not claim. Flag it so it is not picked up next month either.

The dangerous one is the first. Credit you have claimed that your supplier never reported does not announce itself — it sits quietly until scrutiny, by which point interest has been accruing and the supplier may no longer be reachable.

Getting a supplier to actually fix it

Chasing works on a schedule and stops working off it. Before their return is filed, an amendment is trivial. Afterwards it needs a correction in a later period, and their accounts team has moved on.

• Start by the 8th. Suppliers’ GSTR-1 is due on the 11th; before that, fixing an invoice is trivial for them.
• Send specifics, not a spreadsheet. Invoice number, date, value, tax, and the GSTIN it should have been reported against. Vague requests get ignored.
• Escalate commercially. A polite note that payment is on hold pending correct reporting resolves what six emails to accounts will not.
• Make it contractual. New vendor terms should require timely and correct GST reporting, and make payment conditional on credit appearing.

Controls that stop it recurring

1. Validate every vendor GSTIN at onboarding. A wrong number in your master data generates a mismatch every single month. Our GSTIN validator catches malformed numbers instantly.
2. Reconcile monthly, never in arrears. The work is roughly linear per month and roughly exponential once you are a year behind.
3. Track a chase log. Which supplier, which invoice, chased when, promised when. Without it the same twelve invoices get re-discovered every month.
4. Report credit at risk. The rupee value of claimed-but-unmatched credit belongs in your monthly MIS pack, because it is a real contingent liability.
5. Hold a rolling cut-off. Purchases booked to a fixed date each month so the register you reconcile is actually complete.

What ignoring this costs

Three separate costs, and businesses usually only see the first.

• Credit permanently lost where a supplier never reports and time limits pass.
• Reversal with interest on credit claimed that was never available — the one that shows up years later.
• Late-filing cost when the reconciliation is not ready and the return slips. Our late fee calculator sizes that one.

None of this is difficult work. It is repetitive work with a hard deadline, which is a different problem — and the reason it tends to be the first thing dropped in a busy month.

If that is where you are, it is exactly what our GST and TDS compliance service runs: the reconciliation done before the return goes out, a tracked chase log, and credit at risk reported to you monthly rather than discovered at assessment.