See both the within-state (CGST+SGST) and between-state (IGST) breakdown for the same sale amount.
Both scenarios collect the same total tax — only how it's split (and which government collects which part) differs by whether the buyer and seller are in the same state.
CGST + SGST: Each exactly half the total GST
IGST: The full GST amount, unsplit
The same sale can be taxed in two ways under GST, depending on where the buyer is. If the buyer is in the seller's state, the tax is split into CGST and SGST. If the buyer is in another state, it is charged as one IGST. This calculator shows both treatments side by side for the same base price and rate, so you can see that the totals match and only the split changes.
It is handy for sellers who serve customers both inside and outside their state, for accounts staff learning the rules, and for students studying GST. A distributor in Indore who supplies shops in Madhya Pradesh and Rajasthan can use one calculation to prepare both types of invoice. The calculator answers: for this sale, what does each treatment look like?
1. Note the base price B and the GST rate R.
2. Total GST = B × R ÷ 100. This is the same in both treatments.
3. Intra-state: CGST = SGST = total GST ÷ 2.
4. Inter-state: IGST = total GST.
5. In both cases, invoice total = B + total GST.
6. Decide which treatment applies by checking whether the supplier's location and the place of supply are in the same state.
GST was designed so that where the buyer sits should not change the price of a product. The rate on an item is the same whether it is sold locally or across a border. What changes is who collects the tax. In a local sale, the centre and the state each collect half at once. In an inter-state sale, the centre collects the whole amount and later passes on the destination state's share. So CGST + SGST always equals IGST for the same value and rate.
Whether a sale is local or inter-state is decided by the place of supply rules, not by where it is easiest to bill. For goods, it is usually where the movement of goods ends. For services, the rules vary by type of service, and are often the location of a registered recipient. Getting this wrong means charging the wrong tax. The seller then has to pay the correct tax and claim back the wrong one through a separate refund process.
A buyer's input tax credit follows the tax type on the invoice. IGST credit can be set off against all three taxes, CGST credit against CGST and IGST, and SGST credit against SGST and IGST. A business that buys mostly from other states and sells locally will build up IGST credit and use it against local CGST and SGST. Seeing both splits together makes these credit flows easier to follow.
Imran, a distributor of kitchen appliances in Indore, is pricing an order worth ₹75,000 before tax that attracts 18% GST. He supplies shops in both Madhya Pradesh and Rajasthan and wants to see both invoice formats.
Answer: If intra-state: CGST + SGST ₹6,750 + ₹6,750; If inter-state: IGST ₹13,500
Adding IGST on top of CGST and SGST for the same sale.
Assuming inter-state buyers pay more tax.
Deciding the treatment by the buyer's head office when the place of supply is elsewhere.
Rounding each half separately in a way that makes CGST and SGST unequal.
Preparing invoices for both local and out-of-state customers.
Training accounts staff on CGST, SGST and IGST.
Explaining to customers why their invoice shows a different tax split.
Classroom teaching of GST structure.
Does the buyer pay more for an inter-state purchase?
No. The total tax amount stays the same either way. Only how it is split between the central and state government is different.