Since 1 January 2022, you can claim ITC only on invoices that appear in your GSTR-2B (Section 16(2)(aa)). So every month, before filing GSTR-3B, you need to know: which of my purchase invoices are in 2B, which aren't, and which are in 2B but not in my books.
Step 1: get clean data
- GSTR-2B: download the Excel from the portal (Returns → GSTR-2B → Download). Use the B2B, B2BA (amendments) and CDNR (credit/debit notes) sheets.
- Purchase register: export from Tally, Zoho, Busy or your accounting software with supplier GSTIN, invoice number, date, taxable value, IGST, CGST, SGST.
Step 2: match on the right key
Match on supplier GSTIN + invoice number, then compare amounts. Two clean-ups make most "mismatches" disappear:
- Normalise invoice numbers: "INV/24-25/0458", "INV-458" and "458" are often the same invoice. Strip prefixes, slashes, leading zeros and the financial-year tag before comparing.
- Tolerance: allow a rupee or two of round-off difference in tax.
Step 3: sort into five buckets
| Bucket | What it means | Action |
|---|---|---|
| Matched | Same invoice, same tax | Claim ITC |
| Amount mismatch | Same invoice, different tax | Check which is right; ask supplier to amend or correct your books |
| In books, not in 2B | Supplier hasn't filed / filed late / wrong GSTIN | Don't claim now; follow up; claim when it appears |
| In 2B, not in books | Missing purchase entry, or invoice not yours | Book it if genuine; reject in IMS if not |
| Other period | Invoice date in an earlier month, now in 2B | Claim now (within the Section 16(4) time limit) |
Step 4: use IMS before 2B is final
Since 1 October 2024, the Invoice Management System (IMS) lets you accept, reject or keep pending each supplier invoice before your GSTR-2B is generated. Invoices you take no action on are deemed accepted. Reject invoices that aren't yours or are wrong; keep pending those you're still checking. 2B is regenerated after your IMS actions.
Step 5: claim in 3B and track what's deferred
Claim the matched and "other period" ITC in GSTR-3B. Keep a running list of deferred invoices and follow up with those suppliers - email them the list.
Deadlines to remember
- Section 16(4): ITC for a year must be claimed by 30 November of the next year (or the annual return date, if earlier).
- 180-day rule: if you haven't paid the supplier within 180 days of the invoice, reverse the ITC with interest; re-claim when you pay.
- Rule 37A: if the supplier hasn't filed GSTR-3B for the period by 30 September, reverse that ITC by 30 November.
The free in-browser reconciler does steps 2-3 for you: upload both files and get the five buckets plus ready supplier follow-up emails. Nothing leaves your browser.