Input tax credit, in plain words
GST is designed to tax only the value you add — not the full price, over and over, at every step of the chain. The mechanism that makes this work is input tax credit: the GST you paid on business purchases becomes a credit in your electronic ledger, and you use that credit to pay the GST you collect on sales. Only the difference leaves your bank account.
Say you run a furniture business. You buy timber and fittings for ₹3 lakh and pay ₹54,000 GST on them. You sell finished furniture for ₹5 lakh and collect ₹90,000 GST from customers. Without ITC you would owe the full ₹90,000. With it, the ₹54,000 you already paid your suppliers counts — you deposit only ₹36,000 in cash. The government still receives ₹90,000 in total; it just arrives from every link in the chain in proportion to the value each one added.
That is also why keeping purchases inside the GST system matters. Buy from an unregistered supplier and there is no tax invoice, no credit, and the “cheaper” quote quietly costs you 18% more than it looks.
The conditions before a credit is yours
ITC is not automatic — four conditions have to hold. You need a proper tax invoice from a GST-registered supplier. You must have actually received the goods or services. Your supplier must have reported the invoice in their return and paid the tax — which is why the invoice has to appear in your GSTR-2B; if the supplier doesn’t file, your credit doesn’t show up, however genuine your invoice is. And you must claim the credit in time: by 30 November following the end of the financial year, or the date of your annual return, whichever is earlier.
The GSTR-2B condition is the one that bites in practice. It quietly makes you responsible for your suppliers’ compliance — a vendor who delays filing blocks your working capital. Established businesses check 2B before paying vendor invoices for exactly this reason, and many hold back the GST portion until the invoice appears.
Blocked credits — where ITC is simply not allowed
Section 17(5) blocks credit on a specific list, no matter how business-related the expense feels: food and beverages, outdoor catering, club and gym memberships, personal-use motor vehicles (cars up to 13 seats — unless you are in the business of transport, driving schools or resale), works-contract and construction costs for buildings on your own account, goods lost or given away as free samples, and anything bought for personal consumption.
The everyday consequence: the GST on your team lunch or your office car’s insurance is a cost, not a credit. If a meaningful slice of your spending sits in these categories, use the “share of purchases eligible” slider above to see your realistic cash liability rather than the optimistic one.
| Sales ₹5,00,000 → output tax | ₹90,000 |
| Purchases ₹3,00,000 → GST paid | ₹54,000 |
| Net GST to deposit in cash | ₹36,000 |
| Same month with no ITC claimed | ₹90,000 — 2.5× more |
When credit exceeds output tax
Buy heavily in a lean sales month — stocking up before the festive season, say — and your ITC can exceed the tax you collected. Nothing is lost: the unused credit sits in your electronic credit ledger and offsets next month’s liability. Cash refunds of accumulated credit exist only in special cases, mainly exports and inverted duty structures (where your inputs are taxed at a higher rate than your outputs).
One more boundary worth knowing: composition-scheme dealers — the flat-rate option for small businesses — cannot claim ITC at all, and cannot pass credit on to buyers either. If most of your customers are GST-registered businesses, that alone is usually reason to stay in the regular scheme.