If you run a shop in India and you are registered under GST, you pay GST every time you buy stock and you collect GST every time you sell. Input tax credit is the rule that stops you from paying tax twice on the same goods. This guide explains what is input tax credit in GST with example numbers from a typical retail shop, the conditions you must meet to claim it, the 180-day payment rule, the credits you can never claim, and why careful purchase entry decides how much credit you actually get.
Input tax credit in GST, in plain words
Input tax credit (ITC) is the GST you paid on your purchases, which you are allowed to subtract from the GST you collect on your sales. You then deposit only the difference with the government.
Think of it this way. When a wholesaler sells you biscuits, the GST on that bill is your “input tax”. When you sell those biscuits to your customers, the GST on your bills is your “output tax”. At the end of the tax period you work out:
GST payable = Output tax on sales − Input tax credit on eligible purchases
Because every business in the chain claims credit for what was paid before it, tax is effectively charged only on the value added at each step. That is the whole idea behind GST being a value-added tax.
Who can claim input tax credit?
- Regular GST-registered businesses can claim ITC on purchases used for their business.
- Composition scheme dealers cannot claim ITC. They pay tax at a fixed rate on turnover and issue a bill of supply instead of a tax invoice. If you are unsure which document you should issue, read our guide on bill of supply vs tax invoice.
- Unregistered businesses cannot claim ITC at all.
- If you sell both taxable and exempt goods (for example, packaged items and fresh vegetables), credit on common purchases has to be split, and the part related to exempt sales cannot be claimed.
What is input tax credit in GST with example: a retail shop’s month
Let us take an illustrative example of a general store in Kochi that buys from a wholesaler in Kerala, so both purchases and sales are intra-state and carry CGST plus SGST. We use an 18% rate only to keep the maths simple; your actual rates depend on the HSN of each item.
Step 1: The purchase
The shop buys goods worth ₹1,00,000 from a registered wholesaler. The tax invoice shows:
- Taxable value: ₹1,00,000
- CGST at 9%: ₹9,000
- SGST at 9%: ₹9,000
- Invoice total: ₹1,18,000
The ₹18,000 GST is the shop’s input tax.
Step 2: The sales
During the month the shop sells the same goods for a taxable value of ₹1,30,000. Its billing software adds:
- CGST at 9%: ₹11,700
- SGST at 9%: ₹11,700
- Total output tax: ₹23,400
Step 3: The set-off
| Head | Output tax | Input tax credit | Paid in cash |
|---|---|---|---|
| CGST | ₹11,700 | ₹9,000 | ₹2,700 |
| SGST | ₹11,700 | ₹9,000 | ₹2,700 |
| Total | ₹23,400 | ₹18,000 | ₹5,400 |
Without ITC the shop would pay ₹23,400. With ITC it pays ₹5,400, which is exactly 18% of the ₹30,000 value it added (₹1,30,000 − ₹1,00,000). The ₹18,000 was already paid to the government by the wholesaler, so it is not lost.
What if the purchase was from another state?
If the same shop had bought from a supplier in Tamil Nadu, the invoice would show IGST of ₹18,000 instead of CGST and SGST. That IGST credit can be used against IGST, CGST and SGST liability, but the law fixes the order: IGST credit is used up first. CGST credit can never pay SGST and SGST credit can never pay CGST. Good billing software keeps these heads separate so your return figures match. For more on inter-state bills, see how GST is applied in our GST billing software guide for retail shops.
The four conditions to claim ITC (Section 16)
Paying GST on a purchase does not automatically give you credit. Under Section 16 of the CGST Act, all of these must be true:
- You have a valid tax invoice or debit note from a registered supplier, showing your GSTIN, the supplier’s GSTIN, the tax amounts and the other details the rules require. A cash memo or an estimate without GST details is not enough.
- You have actually received the goods or services. If goods come in lots against one invoice, credit is available when the last lot arrives. Goods delivered to a third party on your instruction count as received.
- The supplier has paid the tax to the government and filed their returns. In practice, the invoice must appear in your auto-generated GSTR-2B statement on the GST portal.
- You have filed your own return (GSTR-3B) in which the credit is claimed.
There is also a time limit. Credit for an invoice of a financial year must be claimed by 30 November of the next financial year or the date you file the annual return, whichever comes first. Missed invoices after that date are lost for good, so do not leave purchase bills in a drawer.
Why GSTR-2B matters to a shop owner
GSTR-2B is the statement of purchases your suppliers reported against your GSTIN. If a supplier files late, enters your GSTIN wrong, or forgets an invoice, it will not show in your GSTR-2B and you generally cannot claim that credit until it does. Matching your purchase register with GSTR-2B every month is the single best habit for protecting your ITC. If you also file GSTR-1 from your billing data, our guide on preparing GSTR-1 from billing software shows how the sales side fits in.
The 180-day payment rule
Many shops buy on credit from wholesalers. GST law allows this, but with a condition: you must pay the supplier the invoice value, including tax, within 180 days of the invoice date. If you do not, the ITC you already claimed on that invoice must be reversed by adding it to your output tax, along with interest. Once you finally pay the supplier, you can claim the credit again.
In our Kochi example, suppose the ₹1,18,000 bill was dated 1 April and the shop still owed the full amount on 28 September, the 180th day. The ₹18,000 credit would have to be reversed in the return for that period. This is why supplier dues and GST are connected: a payables report that shows ageing by invoice date helps you clear old bills before they hit 180 days.
Blocked credits: what you can never claim (Section 17(5))
Some purchases are blocked from ITC even if you have a proper invoice. The ones shop owners run into most often are:
- Motor vehicles for carrying people with up to 13 seats, including the owner’s car, unless you are in the business of selling or renting such vehicles or training drivers.
- Food and beverages, outdoor catering, for example staff lunch or a function at the shop, with narrow exceptions.
- Beauty treatment, health services, club or gym memberships, and life or health insurance, unless the law makes them compulsory for employers or you sell the same service.
- Construction of a building, such as building or renovating your shop premises, when the cost goes into the immovable property. Plant and machinery is an exception.
- Goods lost, stolen, destroyed, written off, or given away as gifts or free samples. If stock is damaged in a flood or expires and is written off, the credit taken on it must be reversed.
- Goods or services used for personal consumption by the owner or family.
The full list is longer and has conditions, so check the official text on the CBIC GST portal or ask your tax consultant before claiming anything you are unsure about.
Returns, discounts and credit notes
ITC changes when the purchase changes. If you return goods to a supplier and they issue a credit note, the GST in that credit note reduces your eligible credit. If the supplier later charges extra through a debit note, you can claim the additional tax. Keep these documents linked to the original invoice so your figures stay clean. We cover the process step by step in purchase return software for shops and debit note and credit note software for GST.
Why purchase entry accuracy decides your ITC
Most lost credit in small shops is not about law. It comes from small entry mistakes:
- Wrong supplier GSTIN in your purchase entry, so your register never matches GSTR-2B.
- Invoice number or date typed differently from the supplier’s bill, which makes reconciliation slow.
- CGST/SGST entered as IGST or the other way around, which puts credit in the wrong head.
- Purchases never entered because the bill came with the goods and got lost at the counter.
- Personal or blocked expenses mixed with stock purchases, which inflates the credit and invites notices.
A simple monthly ITC routine for shops
- Enter every purchase bill on the day the goods arrive, with the supplier GSTIN, invoice number and date exactly as printed.
- Check that the items, quantities and tax heads match the physical bill and the stock received.
- After the 14th of the following month, download GSTR-2B from the GST portal and match it with your purchase register.
- Call suppliers whose invoices are missing or wrong, and ask them to correct their filing.
- Review supplier dues older than about 150 days so nothing crosses the 180-day line.
- Exclude blocked items and reverse credit on stock that was written off.
- Claim the matched credit in GSTR-3B and keep the working sheet with your records.
How billing software helps you keep your ITC
When purchases and sales live in the same system, tax heads, GSTINs and invoice numbers are captured once and reused, rather than retyped in three places. Caddayn Biller is GST billing and inventory software for Indian shops, supermarkets, restaurants and pharmacies, so stock received, sales bills and GST figures stay connected. If you want to see how it would handle your shop’s purchases and GST reports, download Caddayn Biller and try it with a few of your own bills. You can also read about creating compliant bills in our GST invoice software guide.
Frequently asked questions
Can I claim input tax credit on purchases from an unregistered dealer?
Normally no, because an unregistered dealer does not charge GST and there is no tax invoice. Where tax is paid by you under reverse charge on a notified supply, you can usually claim that tax as credit once it is paid.
Can a composition dealer claim ITC?
No. Businesses under the composition scheme cannot claim input tax credit and cannot pass on GST to customers through their bills.
What happens if my supplier does not file their return?
The invoice will not appear in your GSTR-2B, and you generally cannot claim the credit until the supplier reports it. Follow up quickly, and consider whether to hold back the GST portion of payment until the invoice shows up.
Is ITC available on shop furniture, computers and billing machines?
Generally yes, capital goods used for business are eligible, as long as they are not in a blocked category and you do not also claim depreciation on the tax portion under income tax.
Can unused ITC be carried forward?
Yes. If your credit is more than your output tax in a month, the balance stays in your electronic credit ledger and is used in later months.
This article is general information for shop owners and is not tax advice. GST rules change from time to time, so confirm the current position with the CBIC notifications or your tax consultant.