CGST, SGST, and IGST Explained Simply

I remember when GST launched on July 1, 2017 — the entire business community in India was in a state of panic. Shop owners in Chandni Chowk, IT service providers in Bengaluru, textile traders in Surat — everyone was asking the same question: "What is this CGST, SGST, IGST business? Why can't they just have one simple tax?" I hear you. And honestly, once you understand the logic behind it, it actually makes sense. Let me break it down in a way that will click for you in the next few minutes.

Why Does GST Have Three Components?

Before GST, India had a complicated web of taxes — VAT, excise duty, service tax, CST, octroi, and more. Each state had its own rules. The whole point of GST was to unify these into one tax. But here's the thing: India is a federal country. Both the Central Government and State Governments have the constitutional right to levy taxes. You can't just tell 28 states and 8 UTs that they no longer get to collect taxes.

So the solution was to split GST into components that preserve this dual taxation structure:

• CGST goes to the Central Government
• SGST goes to the State Government
• IGST is collected by the Centre on inter-state transactions and then shared with the destination state

The total tax amount the buyer pays is always the same. Only the split changes based on whether the sale is within a state or across states. That's the entire concept in a nutshell.

CGST — Central Goods and Services Tax

CGST is the portion of GST that goes to the Central Government on every intra-state (same state) transaction. It is levied under the CGST Act, 2017.

When a furniture shop in Jaipur sells a table to a customer in Jodhpur, both are in Rajasthan, so it's an intra-state sale. The GST is split into CGST (central share) and SGST (state share). If the GST rate on furniture is 18%, then 9% goes as CGST and 9% goes as SGST.

CGST revenue is used by the central government for national defense, infrastructure, central schemes, and other union-level expenditures. The key thing to remember: CGST never appears alone on an invoice — it always appears alongside SGST (or UTGST for Union Territories).

SGST — State Goods and Services Tax

SGST is the state's share of GST on intra-state transactions. It is levied under each state's respective SGST Act. Every state in India has passed its own SGST legislation — so technically, there's a Maharashtra SGST Act, a Karnataka SGST Act, a Tamil Nadu SGST Act, and so on. The rates are identical, but the legal framework is state-specific.

SGST revenue stays with the state where the transaction happens. This is crucial because states use this revenue for local infrastructure, education, healthcare, and state-level schemes. Before GST, states earned this revenue through VAT — now SGST replaces VAT.

Let me give you a practical example. Say you run a printing shop in Ahmedabad, Gujarat. A local business orders visiting cards worth ₹5,000. The GST rate on printing services is 18%. Your invoice will show:

• Taxable value: ₹5,000
• CGST @ 9%: ₹450
• SGST @ 9%: ₹450
• Total: ₹5,900

That ₹450 CGST goes to Delhi (Central Government), and the ₹450 SGST stays in Gujarat. Simple.

IGST — Integrated Goods and Services Tax

IGST is the tax applied on inter-state transactions — when the seller and buyer are in different states. It's collected entirely by the Central Government, which then settles the state's share with the destination state later.

Think of IGST as a mechanism to handle cross-border (cross-state) transactions smoothly. Before GST, inter-state sales attracted CST (Central Sales Tax) at 2%, and the whole system was messy. IGST simplified this dramatically.

Let me tell you why IGST exists as a single tax instead of split CGST+SGST. If a seller in Maharashtra sells to a buyer in Karnataka, which state's SGST would apply? Maharashtra (where the seller is) or Karnataka (where the buyer is)? To avoid this confusion, the government created IGST — one unified rate collected by the Centre, which then distributes the state's portion to Karnataka (the destination state). This is called the destination principle.

IGST on Imports

When you import goods into India, IGST is levied on the imported goods (along with customs duty). This is true whether you're importing electronic components in Chennai or garments in Mumbai. The IGST on imports can be claimed as Input Tax Credit, which is a huge relief for importers.

The Golden Rule — When to Apply Which Tax

Detailed Examples with Real Scenarios

Example 1: Kirana Store in Delhi — Intra-State Sale

Ramesh runs a small grocery shop in Karol Bagh, Delhi. He sells ₹1,000 worth of packaged food items (GST rate: 12%) to a local customer.

• Taxable value: ₹1,000
• CGST @ 6%: ₹60 (goes to Central Government)
• SGST @ 6%: ₹60 (goes to Delhi Government)
• Invoice total: ₹1,120

Example 2: Delhi Seller to Uttar Pradesh Buyer — Inter-State Sale

Now Ramesh gets a bulk order from a shop owner in Noida, Uttar Pradesh. Same goods, ₹1,000 value, 12% GST. But since Delhi and UP are different states:

• Taxable value: ₹1,000
• IGST @ 12%: ₹120 (collected by Centre, UP gets its share later)
• Invoice total: ₹1,120

Notice how the customer pays the same ₹1,120 in both cases. The only difference is what appears on the invoice and where the tax money goes.

Example 3: IT Services Company in Hyderabad

Priya runs a software development firm in Hyderabad, Telangana. She has two clients:

• Client A: A startup in Hyderabad — Same state, so the invoice shows CGST 9% + SGST 9% on the service fee.
• Client B: A company in Pune, Maharashtra — Different state, so the invoice shows IGST 18%.

For services, the "place of supply" is generally the location of the recipient. So even if Priya does the work from Hyderabad, what matters is where the client is located.

Example 4: E-commerce Seller on Amazon

Arjun sells phone covers on Amazon. His business is registered in Gujarat, and his inventory is in an Amazon warehouse in Maharashtra. A customer in Tamil Nadu orders a cover worth ₹500 (GST 18%).

Where is the "supply" happening? The goods move from Maharashtra (warehouse) to Tamil Nadu (customer). Since these are different states, it's an inter-state supply. Arjun charges IGST 18% = ₹90.

But wait — there's a nuance. If Arjun had his warehouse in Gujarat and shipped to a customer in Gujarat, it would be intra-state (CGST + SGST). E-commerce sellers need to be especially careful about this because their inventory might be in multiple warehouses across states.

Example 5: Textile Business in Surat

A textile trader in Surat, Gujarat sells sarees worth ₹10,000 to a retailer in Kolkata, West Bengal. The GST rate on sarees above ₹1,000 is 12%.

• Taxable value: ₹10,000
• IGST @ 12%: ₹1,200
• Total: ₹11,200

If the same trader sold to a shop in Vadodara, Gujarat:

• CGST @ 6%: ₹600
• SGST @ 6%: ₹600
• Total: ₹11,200 (same amount, different split)

What is UTGST (Union Territory GST)?

UTGST replaces SGST for Union Territories that don't have their own legislature. These UTs include:

• Chandigarh
• Lakshadweep
• Dadra and Nagar Haveli and Daman & Diu
• Andaman and Nicobar Islands
• Ladakh

Union Territories with a legislature — Delhi and Puducherry (and now Jammu & Kashmir) — have their own SGST, not UTGST.

The rate is exactly the same as SGST. So if a shop in Chandigarh sells goods locally at 18% GST, the invoice shows CGST 9% + UTGST 9%. For all practical purposes, just treat UTGST the same as SGST — only the name is different.

Place of Supply — The Key Concept

The entire CGST/SGST vs IGST decision depends on one thing: is the transaction intra-state or inter-state? And that depends on the place of supply. This concept trips up a lot of business owners, so let me explain it clearly.

Place of Supply for Goods

• With movement: Where the goods are delivered to the buyer (destination)
• Without movement (installed/assembled at site): Where the goods are installed or assembled
• Bill-to-ship-to: Where the goods are delivered (the "ship to" address, not the "bill to")

Place of Supply for Services

• General rule: Location of the service recipient
• Immovable property (construction, interior design): Where the property is located
• Restaurant/catering: Where the food is served
• Events/exhibitions: Where the event takes place
• Transportation of goods: Where the goods are handed over

I've seen so many invoicing errors because the seller assumed the "place of supply" is their own location. It's not. For most services, it's the recipient's location. A web developer in Bengaluru serving a client in Delhi has an inter-state supply — IGST applies, not CGST+SGST.

ITC (Input Tax Credit) Cross-Utilization Rules

This is where things get interesting, and honestly, this is the part most articles skip. When you pay GST on your purchases (inputs), you can claim that as credit against the GST you collect on your sales. But there are rules about which credit can be used against which tax:

ITC of	Can be used against	Cannot be used against
IGST	IGST first, then CGST, then SGST	—
CGST	CGST first, then IGST	SGST
SGST	SGST first, then IGST	CGST

Let me give a practical example. Suppose you're a manufacturer in Pune. You buy raw materials from Mumbai (intra-state, so you pay CGST + SGST). You then sell the finished product to a dealer in Chennai (inter-state, so you collect IGST).

• CGST ITC from purchases: ₹5,000
• SGST ITC from purchases: ₹5,000
• IGST liability on sales: ₹12,000

You can use ₹5,000 CGST credit + ₹5,000 SGST credit against your ₹12,000 IGST liability. Remaining ₹2,000 IGST you pay in cash. This cross-utilization is what makes the system work smoothly despite the multiple tax heads.

Common Confusion Scenarios

Scenario 1: Branch Transfer Between States

If you transfer goods from your warehouse in Gujarat to your branch in Maharashtra, it's treated as an inter-state supply even though no sale happened. You need to issue a delivery challan and charge IGST on the open market value of the goods.

Scenario 2: Freelancer Working Remotely

If you're a freelance graphic designer registered in Karnataka and your client is in Maharashtra, it's inter-state — IGST applies. Even if you never physically go to Maharashtra. The place of supply for services is the recipient's location.

Scenario 3: SEZ (Special Economic Zone) Supplies

Supplies to an SEZ unit are treated as inter-state supplies, even if the SEZ is in the same state as the supplier. So if your business and the SEZ are both in Karnataka, you still charge IGST (or supply at zero rate with a Letter of Undertaking).

Scenario 4: Multiple GSTINs in the Same State

Some large businesses have multiple GSTINs in the same state (for different verticals or business units). Supplies between these GSTINs within the same state are still intra-state — CGST + SGST applies.

Common Mistakes to Avoid

• Charging IGST for same-state sales: I've seen invoices from shops in Delhi charging IGST to Delhi customers. This is incorrect and causes ITC mismatches when the buyer files their return. The buyer's GSTR-2B won't match, and reconciliation becomes a nightmare.
• Charging CGST+SGST for inter-state sales: Always use IGST for different states. If you get this wrong, the tax goes to the wrong state, and you may face demand notices.
• Confusing place of supply for services: A CA firm in Mumbai providing audit services to a company in Bengaluru must charge IGST, not CGST+SGST. The place of supply is the recipient's location.
• Wrong rate splits: CGST and SGST are always exactly equal halves. There's no scenario where CGST is 10% and SGST is 8%. If the total rate is 18%, it's always 9% + 9%.
• Ignoring place of supply for bill-to-ship-to: When the billing address and shipping address are in different states, the place of supply is where the goods are shipped, not where the bill is sent.
• Not updating invoicing software: If your invoicing tool doesn't automatically handle CGST/SGST vs IGST based on state codes, you're prone to errors. Use a tool like BillCraft that does this automatically.

Quick Reference Table — GST Rate Splits

Total GST Rate	CGST (Intra-State)	SGST/UTGST (Intra-State)	IGST (Inter-State)
5%	2.5%	2.5%	5%
12%	6%	6%	12%
18%	9%	9%	18%
28%	14%	14%	28%
0.25% (rough diamonds)	0.125%	0.125%	0.25%
3% (gold, silver)	1.5%	1.5%	3%

How BillCraft Handles This Automatically

One of the things I appreciate most about BillCraft is that you don't need to worry about any of this manually. When you create an invoice, you simply enter the seller's state and the buyer's state. The app automatically determines whether to apply CGST+SGST or IGST, calculates the correct split, and formats your invoice accordingly. No guesswork, no errors, no ITC mismatch headaches.

For businesses dealing with customers across multiple states — which is increasingly common thanks to e-commerce — this automatic handling is not just convenient, it's essential. One wrong tax type on an invoice can cascade into return filing errors, ITC denials for your buyer, and eventual demand notices from the GST department. Let BillCraft handle the tax logic while you focus on your business.