Input Tax Credit, Explained Simply

The basic idea

Input Tax Credit lets you reduce the GST you owe on your sales by the GST you've already paid on your business purchases — so tax isn't charged again and again at every step of a supply chain. In practice, this is what keeps GST from compounding into a much larger effective tax rate than the headline number suggests.

The conditions that actually matter

• You need a valid tax invoice from your supplier
• You must have actually received the goods or services
• Your supplier needs to have paid that GST to the government and filed their return — this is why your credit can depend on someone else's compliance, not just your own
• You need to pay your supplier's invoice within 180 days, or the credit gets reversed
• You claim it through your GSTR-3B return

Where credit gets blocked outright

Section 17(5) blocks ITC on certain categories regardless of how correctly everything else is documented — personal-use motor vehicles, personal consumption, gifts, and construction of immovable property, among others. Claiming the full amount shown in your GSTR-2B without checking these exclusions is one of the most common reasons ITC gets reversed later, with interest.

The deadline that catches people out

ITC for a financial year has to be claimed by 30 November of the following year — practically, in the GSTR-3B filed for September or October. Miss that window and the credit is gone, even if the purchase and invoice were entirely legitimate. Reconciling your books against GSTR-2B monthly, rather than scrambling at year-end, is the difference between catching this in time and losing it.