Two businesses buy the same thing from the same supplier. One claims the credit, one cannot. The difference is rarely the purchase — it is whether the supplier filed, whether the invoice reached the right statement, and whether anyone looked at it in time.
To claim input tax credit you need a valid tax invoice, actual receipt of the goods or services, tax paid by the supplier, the invoice reflected in your GSTR-2B and your own return filed — all five, under Section 16.
The bottom line
The gate: only invoices you accept in the Invoice Management System flow into GSTR-2B, and only what is in GSTR-2B is claimable.
What is barred outright: the Section 17(5) list — motor cars for personal use, food and beverages, personal consumption, most construction — however genuine the business purpose.
The clock inside the claim: pay your supplier within 180 days or reverse the credit with interest.
What input tax credit does
You pay GST on what you buy and collect GST on what you sell. ITC lets you set the first against the second so you remit only the difference.
Collect ₹18,000 of GST on sales, having paid ₹10,000 of GST on inputs, and you send the government ₹8,000 rather than ₹18,000. That mechanism is what makes GST a tax on value added. Without it the tax would cascade at every stage of the chain, which is the problem GST was built to solve.
It is also where businesses lose the most money, in both directions — missing credit they were entitled to, or claiming credit they were not and repaying it with interest.
The five conditions
Section 16 of the CGST Act allows a claim only when every one of these holds:
- you hold a valid tax invoice or debit note;
- you have actually received the goods or services;
- the supplier has paid the tax to the government;
- the supplier has filed their GSTR-1, so the invoice appears in your GSTR-2B; and
- you have filed your own return.
The fourth is the one that catches people, under Section 16(2)(aa). If the invoice is not reflected in your auto-generated GSTR-2B, the credit is not available — however genuine the purchase and however valid the invoice in your hand. Your supplier's filing discipline has become your cash flow problem.
IMS decides what reaches you
The Invoice Management System changed the route credit takes. Every supplier invoice arrives in your IMS dashboard, and you accept, reject or leave it pending. Only accepted invoices flow into GSTR-2B and become claimable.
Two things follow from that. Inaction counts as acceptance, so an invoice you never looked at enters your credit carrying whatever errors it has. And an incorrect invoice you failed to reject becomes a credit you will reverse later with interest attached.
With GSTR-3B already hard-locked and ITC locking expected to follow, a weekly IMS review before GSTR-2B generates on the 14th is now part of the monthly rhythm rather than an optional control. The 2026 tightening turned ITC from a year-end clean-up into a monthly discipline.
Blocked credits
Some ITC is barred permanently under Section 17(5), even on a genuine business purchase:
- motor vehicles for personal use, with exceptions for transport businesses, driving schools and further supply;
- food and beverages, outdoor catering, club memberships and health services, unless used to make an outward taxable supply of the same kind, or where the law obliges you to provide them;
- goods and services for personal consumption;
- works contract and construction of immovable property, other than plant and machinery, and except where that is your business;
- goods lost, stolen, destroyed, or given away as free samples or gifts.
This is a frequent and expensive error, because the spend looks obviously commercial. Check the list before claiming rather than after a notice.
The 180-day payment rule
Claim ITC on a purchase and then fail to pay the supplier within 180 days of the invoice date, and you must reverse that credit with interest. You can re-claim it once the payment goes out.
So the credit is not simply a function of holding an invoice. It is tied to actually paying the people who invoice you, which makes ITC a reason to watch your payables rather than only your receivables.
How long you have to claim
ITC for a financial year must generally be claimed by the earlier of 30 November of the following financial year, or the date you file the annual return. After that the credit lapses.
Inside IMS, invoices left pending can be actioned in a later period, but that outer limit still applies to them. Pending is a queue, not an exemption.
A worked example
A trader's books show ₹2,00,000 of ITC for the month. Reconciling against GSTR-2B changes the picture twice.
₹40,000 of it relates to a supplier who has not filed GSTR-1, so it is not in GSTR-2B and cannot be claimed yet. Another ₹15,000 is GST on a company car used by a director, blocked under Section 17(5).
The correct claim this month is ₹1,45,000. The ₹40,000 comes back once the supplier files, within the time limit. The ₹15,000 is gone for good. A trader who claimed the whole ₹2,00,000 would face reversal plus 18% interest on the difference.
Common mistakes
- Claiming off GSTR-2A rather than GSTR-2B. Only GSTR-2B is a valid basis now.
- Leaving IMS unreviewed. Unactioned invoices are auto-accepted, pulling in credit you did not check.
- Claiming blocked credits under Section 17(5) — the company car, staff meals, personal items.
- Missing the 180-day payment rule and reversing late, or not at all.
- Never reconciling the purchase register against GSTR-2B, so a mismatch becomes a locked-in error.
- Claiming after the time limit, when the credit has already lapsed.
Frequently asked questions
What are the conditions to claim ITC? A valid invoice, receipt of the goods or services, tax actually paid by the supplier, the invoice appearing in your GSTR-2B, and your own return filed.
Can I claim ITC if it is not in my GSTR-2B? No. Under Section 16(2)(aa) the credit is allowed only where the invoice is reflected in your auto-generated GSTR-2B.
What are blocked credits? Credits barred under Section 17(5), such as personal-use motor vehicles, food and beverages, personal consumption and certain construction, even on genuine business spending.
What is the 180-day rule for ITC? If you do not pay the supplier within 180 days you must reverse the ITC with interest, and you can re-claim it after paying.
By when must I claim ITC for a year? By the earlier of 30 November of the following financial year, or the date of filing the annual return.
My supplier has not filed. Is the credit lost? Not necessarily lost, but not claimable yet. It becomes available once they file and the invoice appears in your GSTR-2B, provided that happens inside the time limit.