GST Input Tax Credit: 10 Most Common Errors and How to Fix Them
Incorrect ITC claims are the single largest source of GST notices. This guide covers the 10 most common ITC errors CA firms see across clients — with exact correction procedures for each.
Why ITC Errors Hurt Your Clients the Most
Input Tax Credit (ITC) is the mechanism that prevents cascading taxation — businesses can claim credit for GST paid on purchases and set it off against output GST liability. But the ITC ecosystem under GST is heavily rules-based, and errors in ITC claims carry significant financial and legal consequences: interest at 24% p.a. (for fraudulent excess claims), penalties up to 100% of the tax amount, and in serious cases, registration cancellation. Here are the 10 errors you must watch for.
Error 1: Claiming ITC Not in GSTR-2B
The error: The client claims ITC in GSTR-3B based on the purchase invoice, but the supplier hasn't filed their GSTR-1 yet, so the invoice isn't in GSTR-2B.
The rule: Since January 2022, ITC is restricted to what appears in GSTR-2B. Claiming more triggers an auto-populated mismatch report and eventually an SCN.
Fix: Reconcile GSTR-2B with purchase register every month before filing. For invoices not in GSTR-2B, follow up with the supplier to file their GSTR-1. Claim the ITC only in the month when it appears in GSTR-2B.
Error 2: Claiming Blocked ITC Under Section 17(5)
The error: Claiming ITC on expenses that are specifically blocked: food and beverages, outdoor catering, membership in clubs, rent-a-cab (unless for employees), life insurance, health insurance (unless statutorily obligated), works contract for construction of immovable property, goods or services used for personal consumption.
The rule: These are permanently blocked credits regardless of business use.
Fix: Create a blocked ITC checklist for each client. Train your team to ask: "Does this invoice fall under Section 17(5)?" before claiming ITC. Reverse any incorrectly claimed blocked ITC with interest (18% p.a.).
Error 3: ITC on Motor Vehicles Not Eligible for Transportation of Persons
The error: Claiming ITC on car purchase or maintenance when the vehicle is not used for taxable supply of transportation of persons, driving school, or on merit goods (ambulance).
Fix: Only cars used for transportation of passengers as a business activity, driving school, or as a good/service on which input is specifically allowed qualify. Company cars for employee conveyance — no ITC. Trucks, delivery vehicles — ITC allowed.
Error 4: Not Reversing ITC When Supplier Invoice Is Unpaid for 180 Days
The error: ITC claimed in Month 1 but the corresponding invoice to the supplier is still unpaid 180 days later. The ITC should have been reversed in the return for the month in which the 180-day mark passes.
The rule: Rule 37 of CGST Rules — ITC claimed on invoices not paid within 180 days must be reversed. The ITC can be re-claimed once payment is made.
Fix: Maintain a pending payables register with invoice dates. For each invoice, set a 180-day alert. If unpaid, reverse ITC in GSTR-3B table 4(B)(2) by the due date. Interest @18% on the reversed amount from the original claim date.
Error 5: Proportionate Reversal Not Done for Exempt and Taxable Supplies
The error: The client has both taxable and exempt supplies (e.g., a developer selling residential apartments which are exempt + commercial space which is taxable). ITC on common inputs/capital goods must be reversed proportionately for exempt supplies.
The rule: Rule 42 and 43 — common credit must be proportionately reversed based on the ratio of exempt turnover to total turnover.
Fix: Calculate the exempt/total ratio quarterly. Reverse ITC in GSTR-3B Table 4(B)(1) accordingly. Document the calculation.
Error 6: ITC Claimed on Tax Invoice With Wrong GSTIN
The error: The supplier issued an invoice with an incorrect GSTIN — either wrong state code, wrong PAN, or a typo. The invoice doesn't match the buyer's GSTIN records, creating a mismatch in GSTR-2B.
Fix: Request a corrected invoice or credit note + fresh invoice from the supplier. The supplier must amend their GSTR-1 to correct the invoice. ITC can only be claimed once the corrected invoice appears in GSTR-2B.
Error 7: ITC on Composition Scheme Supplier's Invoice
The error: A composition dealer cannot issue a "Tax Invoice" — they issue a "Bill of Supply" without GST. Buying from a composition dealer doesn't give the buyer any ITC.
Fix: Check the supplier's GST registration type before claiming ITC. Verify whether the supplier is on the composition scheme via GST portal search.
Error 8: Claiming ITC Without Receiving Goods
The error: ITC claimed on "advance" payments to suppliers where goods/services haven't been received yet. ITC is available only on receipt of goods/services, not on advance payments.
Fix: ITC can be claimed only when: (a) tax invoice is received, AND (b) goods/services are actually received. Match delivery challans or GRNs with invoices before claiming ITC.
Error 9: Double-Claiming ITC in GSTR-3B and Purchase Register
The error: A purchase invoice is accidentally entered twice in the purchase register, or ITC is claimed in two different months for the same invoice.
Fix: Monthly reconciliation of GSTR-2B vs purchase register vs GSTR-3B ITC claimed. Unique invoice number tracking prevents duplicates. Any duplicate ITC must be reversed.
Error 10: Not Claiming ITC on Capital Goods in the Right Period
The error: ITC on capital goods (machinery, computers) is available in the tax period when the goods are received and the invoice is obtained — not over multiple years (unlike the old CENVAT credit rules). Many clients mistakenly defer or amortise capital goods ITC.
Fix: Claim the full ITC on capital goods in the tax period of receipt. If the capital good is used partly for personal/exempt use, only proportionate ITC is available, and annual reversal calculations apply under Rule 43.
