Input Tax Credit (ITC) is the core mechanism of the Goods and Services Tax (GST) system in India, preventing the cascading effect of double taxation. For manufacturers, wholesalers, retailers, and e-commerce sellers, claiming every rupee of eligible ITC is crucial for maintaining healthy profit margins. However, claiming ITC requires strict adherence to statutory conditions under Sections 16, 17, and 18 of the CGST Act 2017. This guide covers all mandatory rules, invoice criteria, and reconciliation steps.

What is Input Tax Credit (ITC)?

Input Tax Credit allows a registered taxable person to claim credit for the GST paid on purchases of goods, raw materials, capital assets, packaging materials, and input services used in the course or furtherance of business. When you make taxable outward sales, the GST collected from customers is offset against the ITC balance available in your Electronic Credit Ledger, and only the balance difference must be deposited in cash.

The Four Fundamental Conditions to Claim ITC (Section 16(2))

Under Section 16(2) of the CGST Act, a registered buyer cannot claim any Input Tax Credit unless all four of the following statutory conditions are fulfilled simultaneously:

1. Possession of a Valid Tax Invoice: The buyer must possess a valid tax invoice or debit note issued by a registered supplier, containing all mandatory details prescribed under Rule 46 of the CGST Rules.
2. Actual Receipt of Goods or Services: The goods or services must have been physically received. In cases where goods are delivered in installments or lots against a single invoice, ITC can only be claimed upon receipt of the final installment.
3. Tax Paid to Government by Supplier: The supplier must have actually deposited the collected tax with the government, either in cash or through valid ITC utilization, and reported it in their GSTR-1 return.
4. Filing of Valid GST Return: The buyer must have filed their monthly return in Form GSTR-3B claiming the specific credit.

Mandatory Tax Invoice Requirements for Valid ITC Claims

A tax invoice must contain the following specific information to qualify as a legal ITC-supporting document under Rule 46:

• Supplier's GSTIN, Name, and Registered Address: Must match official GST portal records.
• Buyer's GSTIN, Legal Name, and Billing Address: Critical for B2B transactions; any typo or wrong state code will prevent auto-population in GSTR-2B.
• Unique Consecutive Invoice Number: Alphanumeric sequence up to 16 characters, unique for the financial year.
• Date of Invoice Issue: Must precede or coincide with the supply date.
• HSN/SAC Code: Proper 4-digit or 6-digit Harmonized System code based on annual turnover thresholds.
• Detailed Description & Quantity of Goods/Services: Clear itemization and unit of measurement.
• Taxable Value & Itemized Tax Split: Explicit breakdown of taxable value, applicable rate slab, and separate amounts for CGST, SGST, IGST, and Compensation Cess.
• Place of Supply with State Name & Code: Determines whether the buyer is entitled to intra-state (CGST+SGST) or inter-state (IGST) credit.

Mandatory GSTR-2B Matching Rules (Rule 36(4))

Under current GST law, provisional ITC claims are strictly disallowed. A taxpayer can only claim ITC that is explicitly reflected and marked as "Eligible" in their auto-generated Form GSTR-2B on the GST portal. GSTR-2B is a static monthly statement generated on the 14th of every month based on GSTR-1 returns filed by suppliers by the 11th/13th. If your supplier fails to file their GSTR-1 on time, the invoice will not appear in your GSTR-2B, and you cannot claim ITC for that month until the supplier regularizes their filings.

The 180-Day Supplier Payment Rule (Second Proviso to Section 16(2))

If a buyer fails to pay the supplier the total invoice value along with applicable GST within 180 days from the date of the invoice, the entire ITC claimed on that invoice must be reversed in Form GSTR-3B along with penal interest under Section 50. Once the payment is subsequently made to the supplier, the buyer can re-claim the reversed ITC without any time restriction.

Blocked Credits: Where ITC Cannot Be Claimed (Section 17(5))

Even with a valid GST invoice, ITC is legally blocked on certain business expenses under Section 17(5):

• Motor Vehicles & Conveyances: Passenger vehicles with seating capacity up to 13 persons, unless used for transportation of goods, driving school training, or passenger transport business.
• Food, Beverages, Catering & Hospitality: Food and beverages, outdoor catering, beauty treatment, health services, and club memberships (unless obligatory under government labor laws).
• Personal Consumption: Goods or services procured for personal use of directors, partners, or employees.
• Lost, Stolen, or Destroyed Goods: Inventory damaged, written off, or distributed as free promotional samples.
• Purchases from Composition Dealers: Taxes paid under Section 10 composition scheme.

Statutory Time Limit for Claiming Past ITC (Section 16(4))

ITC relating to any invoice or debit note for a financial year must be claimed on or before the 30th day of November following the end of the financial year, or the actual date of filing the annual return (Form GSTR-9), whichever is earlier. For example, for FY 2025-26, all un-claimed ITC must be accounted for in returns filed up to November 30, 2026.