Why reconcile with GSTR-2B
Under s.16(2)(aa) of the CGST Act, you can claim input tax credit only when the supplier has reported the invoice in GSTR-1 or IFF and it appears in your GSTR-2B. Rule 36(4) limits credit to what 2B shows. An invoice in your books but missing from 2B is credit you cannot claim this month. Follow it up with the supplier until it appears. If it appears in a later 2B, claim it in that month, but no later than 30 November after the year ends (s.16(4)).
IMS and the 2B you download
Since October 2024, GSTR-2B is built from your actions in the Invoice Management System (IMS). Accepted and pending records are carried into it, and rejected ones are left out. From the October 2025 tax period, credit notes and some downward amendments can be kept pending for one tax period. You can also declare how much credit you actually reverse against a credit note. Run this reconciliation before you act in IMS. Reject only invoices that are not yours. If you reject a real purchase, its credit is lost until the supplier reports it again. After acting, recompute 2B and reconcile again before filing GSTR-3B. Sources: EY summary of the GSTN IMS advisory, September 2025.
What each category means
- Matched: same GSTIN and invoice number, and every amount within the tolerance.
- Amount mismatch: the invoice is in both lists, but the taxable value or a tax head differs. If IGST is in one list and CGST + SGST in the other, the place of supply is wrong on one side. You cannot take IGST credit that was charged as CGST + SGST.
- In books, not in 2B: credit at risk. Ask the supplier to file or correct GSTR-1, or use GSTR-1A, before your return date.
- In 2B, not in books: either not yet booked, or not your purchase. Check before accepting it in IMS.
- Probable match: same supplier and amount but a different invoice number. Usually a typo or a series prefix. The supplier should amend it.
GSTR-3B after the reconciliation
From the July 2025 tax period, the outward liability auto-filled in GSTR-3B from GSTR-1/1A can no longer be edited. Correct sales through GSTR-1A, not 3B. A GSTR-3B cannot be filed more than three years after its due date. The credit side of 3B is filled from 2B, so any reversal you need (Rule 37, Rule 42, ineligible credit) must be entered in Table 4(B). See the Rule 42/43 reversal calculator.
Common questions
Is my data uploaded anywhere?
No. The files are read by JavaScript in your browser and matched there. Nothing is sent to a server, and nothing is saved after you close the tab. The shareable link carries only the tolerance setting, not your data.
How do I get GSTR-2B as CSV?
On the GST portal, go to Returns, then GSTR-2B, and download the Excel. Open the B2B sheet, delete the merged heading rows if you like (the tool skips them anyway), and save it as CSV. Do the same with B2B-CDNR for credit notes and run them separately.
Why are two lines of the same invoice added together?
Purchase registers exported from Tally or an ERP often have one line per item or per tax rate. GSTR-2B has one line per invoice per rate. The tool adds rows with the same GSTIN and invoice number so like is compared with like.
Does a match in 2B guarantee my ITC?
No. You also need the goods or services to have been received, tax to have been paid to the government by the supplier (s.16(2)(c)), payment to the supplier within 180 days (Rule 37), and the credit must not be blocked under s.17(5).