Summary
A business can claim input tax credit only on invoices its suppliers have reported, which appear in its GSTR-2B. Credit is lost or delayed when bills sit in the purchase register but not in the statement, when amounts differ, or when the reconciliation starts too late to chase suppliers before GSTR-3B is due. A monthly routine that starts on the day GSTR-2B is generated, sorts every bill into three lists and chases suppliers in order of credit at risk lets the business claim in full and on time.
01The rules that decide the credit
Only what the supplier reported
Since 1 January 2022, Section 16(2)(aa) of the CGST Act allows credit on an invoice only when the supplier has furnished its details in GSTR-1 and they are communicated to the buyer. Rule 36(4) of the CGST Rules limits the credit to what appears in GSTR-2B.
The other conditions still apply
Under Section 16(2), the buyer must hold a tax invoice, have received the goods or services, the tax must have been paid to the government, and the buyer must have filed its own return under Section 39.
Pay the supplier within 180 days
Under the second proviso to Section 16(2) and Rule 37, credit taken on a bill that is not paid to the supplier within 180 days of the invoice date must be reversed with interest. It can be claimed again once payment is made.
Supplier must file GSTR-3B too
Under Rule 37A, if the supplier has not filed GSTR-3B for the period by 30 September of the following financial year, the buyer reverses the credit by 30 November of that year. It can be re-claimed once the supplier files.
Time limit
Under Section 16(4), credit for a financial year must be claimed by 30 November of the following year or the date of filing the annual return, whichever is earlier.
Interest on wrong claims
Credit wrongly taken and used attracts interest under Section 50(3), at the notified rate of 18 percent a year.
02The monthly timetable
| Date | Event |
|---|---|
| 11th | Suppliers file GSTR-1 for the previous month (monthly filers) |
| Up to the 14th | Invoice Management System (IMS) shows supplier documents as they are filed; the buyer can accept, reject or keep pending |
| 14th | GSTR-2B for the previous month is generated, reflecting IMS actions; documents with no action are treated as accepted |
| 14th to 20th | Buyer reconciles, takes further IMS actions if needed and recomputes GSTR-2B |
| 20th | GSTR-3B due for monthly filers; credit auto-filled from GSTR-2B |
IMS was introduced on the GST portal in October 2024. From the October 2025 tax period, GSTN advisories limit how long a document can be kept pending, and Advisory No. 631 of 17 October 2025 allowed credit notes to be kept pending for one tax period and let the buyer declare the actual credit to reverse when accepting a credit note. Credit still flows from GSTR-2B into GSTR-3B as before.
Two further points affect timing. GSTR-2B is not generated for a buyer whose previous GSTR-3B is still pending; it is computed after that return is filed. And invoices from a supplier who files quarterly under the QRMP scheme reach the buyer's GSTR-2B only after the supplier files its Invoice Furnishing Facility (IFF) by the 13th of the first or second month of the quarter, or its quarterly GSTR-1.
03A reconciliation in three lists
Match each bill in the purchase register to a document in GSTR-2B using the supplier's GSTIN, the invoice number and the date, then compare the taxable value and the tax. Every bill falls into one of three lists.
Matched
GSTIN, invoice number, date and amounts agree within a small tolerance. Accept these in IMS. Before claiming, remove credit that is blocked under Section 17(5), such as on most motor vehicles, food and beverages, and works contracts for immovable property; reverse the share required under Rules 42 and 43 where inputs or capital goods serve exempt supplies too; and hold back credit on goods not yet received at month end. These go in Table 4(B) of GSTR-3B.
Different
The document is in GSTR-2B, but something does not agree.
| Difference | Usual cause | Action |
|---|---|---|
| Invoice number differs slightly | Leading zeros, prefixes or slashes typed differently | Correct the register if it is the same invoice |
| Taxable value or tax differs | Rate applied wrongly by one side, freight added on one side only | Ask the supplier for an amendment or correct the entry |
| Wrong tax type | Supplier charged IGST on an intra-state supply, or the reverse | Supplier must issue a credit note and a fresh invoice |
| Wrong place of supply | Supplier reported the wrong state | Supplier amends in GSTR-1 |
| Supplier used another of its own GSTINs | Supplier billed from a different state registration | Correct the register to the GSTIN on the invoice |
| Supplier billed another of the buyer's GSTINs | Wrong buyer registration on the invoice | The credit belongs to that GSTIN; ask the supplier to amend in GSTR-1 if the invoice was meant for this one |
Missing
The bill is in the register but not in GSTR-2B. The supplier has not filed, has filed late, files quarterly, or has reported the invoice against another GSTIN. The credit cannot be claimed this month. It will appear in a later GSTR-2B once the supplier files, and can be claimed then, provided this is within the Section 16(4) time limit.
The reverse also happens: a document appears in GSTR-2B with no bill in the register. Either the bill has not reached accounts, or the document is not genuine. Find the bill, or reject the document in IMS.
04Chasing suppliers by credit at risk
Sort the missing list by supplier and total the credit at risk for each. The suppliers holding the most credit come to the top, so the first calls go where the money is, with the invoice numbers and amounts in hand.
For suppliers who file late every month, hold part of the payment until the invoice appears in GSTR-2B, where the purchase terms allow it, and record late filing in the supplier's rating. Where the supplier is a micro or small enterprise, the 45-day payment limit under Section 15 of the MSMED Act and the income-tax disallowance for late payment to such suppliers still apply.
What is at stake, worked through. Take a business with ₹2 crore of purchases a month at 18 percent GST, carrying ₹36 lakh of credit. If bills carrying 5 percent of that credit are missing on the 14th, ₹1.8 lakh of credit waits on suppliers this month. Both percentages are assumptions; use your own register.
05Mistakes that cost credit
- Starting on the 18th
- Two days are not enough to chase anyone. Start on the 14th.
- Accepting everything in IMS by default
- A document left without action is treated as accepted. A wrong or fake invoice then flows into GSTR-2B and into the claim.
- Forgetting to recompute
- IMS actions taken after the 14th change the credit only after GSTR-2B is recomputed, before GSTR-3B is filed.
- Not tracking the 180-day rule
- Credit on a bill unpaid after 180 days must be reversed. Keep the supplier payment due list next to the credit list.
- Losing track of re-claims
- Report temporary reversals in Table 4(B)(2) of GSTR-3B. The portal tracks them in the Electronic Credit Reversal and Re-claimed Statement, available since the August 2023 tax period, and a re-claim in Table 4(D)(1) cannot exceed its balance. Keep your own list by invoice as well, so you know which supplier's filing releases which amount.
- Claiming more than GSTR-2B shows
- Where credit claimed in GSTR-3B exceeds GSTR-2B beyond the limits set under Rule 88D, the portal issues an intimation in Form DRC-01C, and the business must pay the difference or explain it within seven days.
06How MatruOS runs it
GSTR-2B brought in and matched
The GSTR-2B file downloaded from the GST portal, in JSON or Excel, is brought into the Accounts area and matched to purchase bills. The screen shows the credit the law allows, the documents that differ, the bills suppliers have not filed with a note ready to send to each supplier, and the IMS decision to take on the portal for each document.
Corrections and rematching
A person can link a document to a different bill, unlink a wrong match, record the IMS decision taken on the portal, and run the match again after corrections.
Bills captured as they arrive
Supplier bills forwarded by email or WhatsApp, or uploaded as files or photos, are read and prepared as purchase entries for a person to confirm, so bills are in the register before GSTR-2B is generated.
AI can make mistakes. Bills read from email, WhatsApp or photos always wait for a person to confirm them. Other purchase entries by AI members wait for a person while bookkeeping is set to Ask me. Review the matches before you take IMS actions on the portal.
Sources
Checked 31 October 2026.
- Central Goods and Services Tax Act, 2017 (CBIC): Sections 16(2), 16(2)(aa), 16(4), 17(5), 50(3).
- CGST Rules, 2017 (CBIC): Rules 36(4), 37, 37A, 42, 43, 88D.
- GSTN Advisory No. 631, 17 October 2025: pending option for credit notes in IMS.
- GST portal news and advisories: IMS, GSTR-2B generation on the 14th, recompute before GSTR-3B.