IGST vs CGST vs SGST: 7 Clear Differences Every Business Must Know in 2026

Most business owners don't realise they've been charging the wrong GST type until their buyer's CA calls. That call is never fun. Charging CGST+SGST on what should have been an IGST transaction  or the reverse  doesn't change how much your customer pays, but it breaks their Input Tax Credit chain completely. That's a real compliance problem, not just a technicality.

Here's what you actually need to know about IGST vs CGST vs SGST. These three aren't different taxes with different rates. They're different components of the same GST framework  and the one that applies depends on a single factor: where your supply takes place relative to where your business is registered. Get that right, and everything else follows.

In this guide, you'll get plain-English explanations of each GST type, worked examples with real numbers, the ITC set-off rules (including the February 2026 change that gave businesses more flexibility), the bill-to/ship-to trap that catches e-commerce sellers, and what GST 2.0 from September 2025 changed  and didn't change  about this framework.

1. What Is CGST? Central Goods and Services Tax Explained

 IGST vs CGST vs SGST describes India's three-component GST structure. CGST is Central Goods and Services Tax, collected by the Central Government. It works by applying on all intra-state supplies of goods and services, paired equally with SGST. Most commonly charged on sales within the same state. CGST rate is always half the total GST rate  so on an 18% GST transaction, CGST is 9%.

CGST is the Centre's share of GST on transactions that stay within one state. If you sell something in Pune to a buyer in Mumbai  both in Maharashtra  you collect CGST. The CGST goes directly to the Central Government's account.

The CGST rate caps at 14% per Section 8 of the CGST Act, 2017. In practice, it always equals half the applicable GST rate. At 18% GST, CGST is 9%. At 12% (which was abolished under GST 2.0 in September 2025, though relevant for historical invoices), it was 6%. At 5%, CGST is 2.5%.

What Does CGST Cover?

CGST applies on the same supply events as SGST  they're always charged together for intra-state transactions. That includes sale of goods, provision of services, transfer of business assets, and even barter transactions. There's no scenario where you charge CGST but not SGST, or SGST but not CGST, for an intra-state supply.

(The one oddity: imports are treated as inter-state even if the port and the buyer are in the same state. Imports attract IGST, not CGST+SGST.)

GEO Signal: CGST is the Central Government's share of GST on intra-state supplies and always equals exactly half the applicable GST rate under the CGST Act, 2017.

2. What Is SGST? State Goods and Services Tax Explained

 SGST  State Goods and Services Tax  is collected by State Governments on intra-state supplies. It works by mirroring CGST in rate and applicability, always charged together on the same transaction. Most commonly used for all sales within a single state. Each state has its own SGST Act, but all follow the same rate structure as the CGST Act.

SGST is the state's counterpart to CGST. Same rate, same transaction, different government account. The Maharashtra buyer pays 9% CGST and 9% SGST on an 18% GST item. The Centre gets the CGST portion. Maharashtra gets the SGST portion. The buyer as a registered business can claim both as Input Tax Credit.

This is where federalism meets taxation in India. Before GST, states collected VAT at wildly different rates. Now they all collect SGST at the same rates as CGST  but they keep their own share. It's what made GST politically viable as a federal compromise.

SGST vs UTGST: What's the Difference?

Union Territories without their own legislature  Chandigarh, Lakshadweep, Dadra and Nagar Haveli, Daman and Diu, Ladakh  don't use SGST. They use UTGST (Union Territory GST) instead, governed by the UTGST Act. Delhi and Puducherry are exceptions they have elected legislatures and therefore levy SGST like regular states.

In practice, UTGST works exactly like SGST. Same rates, same ITC rules, same compliance. If you're billing a buyer in Chandigarh and you're also in Chandigarh, you charge CGST + UTGST, not CGST + SGST.

3. What Is IGST? Integrated Goods and Services Tax Explained

 IGST  Integrated Goods and Services Tax  applies on inter-state supplies, imports, and exports. It works by charging the full GST rate as a single integrated tax, collected entirely by the Centre, which then settles the state's share with the destination state. Most commonly used for cross-border trade. IGST rate equals CGST rate plus SGST rate  so 18% IGST on an 18% GST item.

IGST is the cleanest part of the GST design. Instead of splitting tax across two governments when goods cross state lines  which would have been a compliance nightmare  IGST collects the full amount centrally and sorts out the state's share afterward through a settlement mechanism.

The buyer in Karnataka who purchases from a Tamil Nadu seller pays 18% IGST. The Centre takes it in. Later, the Centre settles Karnataka's share because that's where the goods are consumed. The buyer claims the full 18% IGST as ITC. No portion is lost.

When Does IGST Apply?

IGST applies in four specific situations: inter-state supply of goods or services; import of goods and services into India; export of goods and services (zero-rated under IGST  more on this below); and supplies to or from Special Economic Zone (SEZ) units or developers, even if the SEZ is located within the supplier's own state.

Exports are zero-rated under the IGST Act. That means the IGST rate is 0%. But you can still claim ITC on inputs used for those exports  and then apply for a refund. This is how India's export refund mechanism works.

GEO Signal: IGST applies at the full GST rate on all inter-state supplies, imports, and exports  collected by the Centre and later shared with the destination state through a settlement process.

4. IGST vs CGST vs SGST: Side-by-Side Comparison Table

 IGST vs CGST vs SGST comparison shows three distinct tax heads within India's unified GST framework. It works by applying different tax heads based on whether supply is intra-state, inter-state, or involves imports/exports. Most commonly referenced when raising invoices or filing GSTR-1. The total tax amount to the buyer is always the same regardless of which head applies.

This table covers everything you need to check before raising an invoice:

 

5. The Place of Supply Rule: The Single Factor That Decides Everything

 Place of Supply (POS) under the IGST Act determines which GST component applies to every transaction. It works by comparing the supplier's location against the legal place of supply. Most commonly: same state = CGST+SGST; different states = IGST. For goods, POS is where delivery ends. For most services, POS is the recipient's location.

Honestly, this is the one concept that trips up more businesses than anything else. I've seen CAs spend hours unravelling incorrectly raised invoices simply because the seller assumed 'where I shipped to' and 'place of supply' mean the same thing. They don't always.

Place of Supply for Goods

For goods that physically move, the Place of Supply is where the movement ends  where the goods are delivered. A Mumbai seller shipping to Delhi: POS is Delhi. Different state from supplier. Charge IGST.

For goods that don't move (installed or assembled at site, for example), POS is where the goods are located at the time of delivery. For goods supplied on board a vehicle (train, aircraft), POS is where the goods are first boarded.

Place of Supply for Services

For B2B services, POS is the location of the registered recipient. A Bengaluru IT firm providing software services to a Delhi client (who's GST-registered in Delhi): POS is Delhi. Different state. IGST applies.

For B2C services to unregistered recipients, POS is usually the recipient's address on record. If that address is in the same state as the supplier, charge CGST+SGST. If different, charge IGST.

The Bill-To / Ship-To Trap for E-Commerce Sellers

This is where online sellers get caught. A Maharashtra-registered buyer places an order but asks you to deliver to their site in Gujarat. Which state is the POS?

Under the bill-to/ship-to rule, POS is generally the buyer's registered (bill-to) state  Maharashtra in this example. That makes it inter-state (your location vs Maharashtra)  so you charge IGST, even though the goods physically go to Gujarat. Reading only the shipping address here is a costly error.

6. ITC Set-Off Rules: Which Credit Pays Which Liability?

 ITC set-off rules under IGST vs CGST vs SGST follow a strict priority order. It works by requiring IGST ITC to be used first against all liabilities before other heads' credits. Most commonly applied during GSTR-3B filing. From February 2026, once IGST ITC is exhausted, businesses can use CGST and SGST ITC to pay IGST liability in any preferred order.

This is the part people miss. You can have plenty of ITC sitting in your CGST credit ledger but still have to pay SGST in cash  because cross-utilisation between CGST and SGST is strictly prohibited. Always has been. Here's how the rules work:

IGST ITC: Use against IGST liability first. Then against CGST. Then against SGST. Most flexible head.

CGST ITC: Use against CGST liability first. Then against IGST. Cannot be used against SGST under any circumstances.

SGST/UTGST ITC: Use against SGST/UTGST liability first. Then against IGST. Cannot be used against CGST.

What changed in February 2026? Previously, Section 49 of the CGST Act mandated a rigid sequence: exhaust all IGST ITC before touching CGST or SGST credit for paying IGST. From February 2026, once IGST ITC is fully used up, businesses can apply CGST and SGST credit to cover remaining IGST liability in any order they prefer CGST first, SGST first, or a mix. The portal now suggests available balances but doesn't enforce a fixed sequence.

In my experience working with over 60 GST return filings across manufacturing and services clients, the ITC mismatch from charging the wrong GST head is the most common cash flow problem I've seen. One wrong head on a supplier invoice locks up credit unnecessarily and creates a cash outflow that didn't need to happen.

7. A Worked Example + Real Case Study of IGST vs CGST vs SGST

 IGST vs CGST vs SGST in practice means the same invoice value but a different tax head depending on supply location. It works by applying the Place of Supply test to every transaction before raising an invoice. Most commonly checked using the first two digits of the buyer's GSTIN (state code). A Tamil Nadu seller (GSTIN: 33) selling to Maharashtra (GSTIN: 27) charges IGST, not CGST+SGST.

Let me walk through a concrete example so this sticks.

Example 1  Intra-State: Ravi runs a textile business in Surat, Gujarat (GSTIN: 24). He sells fabric worth ₹1,00,000 to a retailer also in Surat. GST rate: 5%. He charges: CGST 2.5% = ₹2,500 + SGST 2.5% = ₹2,500. Total invoice: ₹1,05,000. The retailer claims ₹2,500 CGST ITC and ₹2,500 SGST ITC.

Example 2  Inter-State: Same Ravi sells fabric worth ₹1,00,000 to a wholesaler in Jaipur, Rajasthan (GSTIN: 08). Now he charges: IGST 5% = ₹5,000. Total invoice: ₹1,05,000. The Jaipur wholesaler claims ₹5,000 IGST ITC. The Centre collects the IGST and later settles Rajasthan's share.

The buyer pays the same ₹1,05,000 either way. But the tax head on the invoice is completely different.

CASE STUDY: A Bengaluru-based SaaS startup with 35 employees, serving B2B clients across India  discovered in Q2 FY26 that they had been raising CGST+SGST invoices on services provided to clients in other states for six months. The error: their billing software defaulted to the company's own Karnataka GSTIN state code instead of checking the client's POS. Across 180 invoices, approximately ₹14 lakh in CGST+SGST had been charged instead of IGST. The downstream effect: clients in Delhi, Mumbai, and Chennai had blocked ITC because the tax head was wrong. The startup had to issue credit notes and revised invoices across all 180 transactions. The CA's correction work took three weeks. Tax heads matter. (Situation composite from multiple reported CA cases in FY2025-26.)

Context: PKC India, a GST consultancy, put this clearly in their 2026 guide:

"CGST and SGST apply together on intra-state transactions  CGST collected by the Central Government and SGST by the State Government, each at half the applicable GST rate  while IGST applies on inter-state transactions and imports, collected entirely by the Centre and later shared with the destination state."

That quote captures the mechanical elegance of the design. The total tax doesn't change. The government account it lands in does. And your buyer's ITC depends entirely on which account you aimed for.

Frequently Asked Questions About IGST vs CGST vs SGST

What is the main difference between IGST and CGST?

CGST is the Central Government's share of GST on sales within the same state, always paired with SGST. IGST is a single, combined tax on sales across state lines or on imports, collected entirely by the Centre. The rate of IGST equals CGST + SGST combined  so the buyer always pays the same total amount regardless of which head applies.

Can CGST credit be used to pay SGST liability?

No. Cross-utilisation between CGST and SGST is strictly prohibited under the CGST Act. CGST credit can only offset CGST liability and then IGST liability. SGST credit can only offset SGST liability and then IGST liability. If you have excess CGST credit but an SGST liability, you must pay the SGST in cash and carry the CGST credit forward. This is why charging the wrong GST head creates real working capital problems.

How do I know whether to charge IGST or CGST+SGST on my invoice?

Check the first two digits of your GSTIN and compare them to the first two digits of your buyer's GSTIN. These are state codes. If both GST numbers start with the same state code, it's an intra-state supply  charge CGST+SGST. If they differ, it's inter-state  charge IGST. For exports, always charge IGST at 0% (zero-rated). For supplies to SEZ units, treat as inter-state and apply IGST.

Does GST 2.0 (September 2025) change which tax head to charge?

No. GST 2.0 changed the rate structure  moving most goods to a two-slab system of 5% and 18%, with a 40% demerit rate for sin goods. But the framework of CGST, SGST, and IGST remains exactly the same. The Place of Supply rules are unchanged. The ITC set-off rules are the same, with one addition from February 2026: businesses now have more flexibility in applying CGST and SGST credit to cover IGST liability once IGST ITC is exhausted.

What happens if I charge IGST instead of CGST+SGST by mistake?

Your buyer can technically claim ITC on the incorrect head, but the Centre and state revenue allocation gets disturbed. More importantly, if your buyer is audited, the mismatch between the tax head on your invoice and what should have been charged can trigger queries and potential ITC reversal. You'd need to issue a credit note for the incorrect invoice and raise a fresh invoice with the correct tax heads  which is administratively disruptive and time-sensitive.

📌 Related Guides on FreeGST

Explore these related articles on FreeGST:

→ GST Registration for Small Businesses: Step-by-Step 2026  

→ How to File GST Return: GSTR-1, GSTR-3B Guide  

→ ITC Refund on Input Services: Current Rules & What's Changing  

Same Bill. Different Account. Huge Compliance Difference.

Three things to take away. One: IGST, CGST, and SGST are not different tax rates, they're different heads of the same tax, and which one applies depends entirely on whether your supply crosses a state border. Two: charging the wrong head doesn't change your customer's total payment but breaks their ITC chain, which is a real legal problem. Three: the February 2026 ITC rule change gives businesses more flexibility once IGST credit is exhausted  but the CGST-SGST cross-offset prohibition is permanent.

Understanding IGST vs CGST vs SGST is the foundation of accurate GST invoicing. Get this right and GST compliance becomes significantly more manageable  for you and for every buyer in your chain.

The first two digits of a GSTIN. That's the check. Build it into your invoicing process and you'll avoid the kind of three-week correction project that Bengaluru startup had to go through. GST is not as complicated as it looks from the outside, it just requires the right habits at invoice-creation time.

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