CGST vs SGST vs IGST — Which to Charge? Formula + Examples 2026
CGST, SGST, and IGST are the three forms of GST in India, and every registered business must know which one to charge. The mistake of applying CGST+SGST on an interstate invoice (or IGST on an intrastate one) is one of the most common GST errors — and it creates significant problems for your buyer's ITC claim.
By Arjun Sharma· GST & Tax Compliance Specialist···Reviewed for GST accuracy
No signup required₹6.31 Cr+ invoice value processedTrusted by 300+ businessesFree forever
Free Tool — No Login Required
Calculate CGST/SGST/IGST Automatically
Auto CGST/SGST/IGST split
PDF in 30 seconds
No signup needed
Free forever
What you get:
GST-compliant PDF
Shareable invoice link
UPI QR on invoice
GSTIN validation
Quick Answer
CGST and SGST are charged together (each at half the GST rate) for intra-state supplies — when the supplier and buyer are in the same state. IGST is charged at the full GST rate for inter-state supplies — when the supplier and buyer are in different states. You never charge both CGST/SGST and IGST on the same invoice. Formula: GST Amount = Taxable Value × GST Rate ÷ 100.
What are CGST, SGST, and IGST?
India's GST has a dual structure mandated under the CGST Act, 2017. Every supply is taxed by both the Centre and the State. The split depends on whether the supply crosses a state border.
Tax
Full Form
Who Gets It
When Applied
CGST
Central Goods and Services Tax
Central Government
Intrastate supply (same state)
SGST
State Goods and Services Tax
State Government
Intrastate supply (same state)
IGST
Integrated Goods and Services Tax
Central Govt (then split)
Interstate supply or import
UTGST
Union Territory GST
UT Administration
Supplies within a Union Territory
The Golden Rule: Intrastate vs Interstate
The "place of supply" rule determines which tax you charge. Place of supply is usually where the buyer receives the goods or where the service is consumed.
Supplier Location
Buyer Location
Tax to Charge
Maharashtra
Maharashtra
CGST 9% + SGST 9%
Maharashtra
Karnataka
IGST 18%
Karnataka
Karnataka
CGST 9% + SGST 9%
Delhi
Punjab
IGST 18%
Chandigarh (UT)
Chandigarh
CGST 9% + UTGST 9%
Important
CGST + SGST always adds up to the same rate as IGST. At 18% GST: CGST = 9%, SGST = 9%. The total tax burden is identical — only who collects it changes.
Skip the manual work
Use Free GST Calculator
Instead of manually formatting invoices in Excel, generate GST-compliant invoices instantly — automatic CGST, SGST & IGST calculation, PDF download, and shareable link.
For intrastate supply, split the GST rate equally between CGST and SGST.
Example
A consultant in Mumbai bills ₹1,00,000 to a client in Pune (both Maharashtra). GST rate = 18%. CGST = ₹1,00,000 × 9% = ₹9,000. SGST = ₹1,00,000 × 9% = ₹9,000. Invoice total = ₹1,18,000.
How to Calculate IGST
For interstate supply, charge the full GST rate as IGST. Do not split it.
Example
A software company in Bengaluru (Karnataka) bills ₹2,00,000 to a client in Hyderabad (Telangana). GST rate = 18%. IGST = ₹2,00,000 × 18% = ₹36,000. Invoice total = ₹2,36,000. No CGST or SGST is shown.
GST Rate Slabs in 2026
GST applies at five main rates. The rate depends on the HSN code (goods) or SAC code (services) of the item:
GST Rate
CGST
SGST/UTGST
IGST
Common Examples
0%
0%
0%
0%
Fresh vegetables, milk, eggs, books
5%
2.5%
2.5%
5%
Footwear <₹1000, printed books, transport services
12%
6%
6%
12%
Butter, cheese, computers, mobile phones
18%
9%
9%
18%
Most services, electronics, branded food
28%
14%
14%
28%
Luxury cars, aerated drinks, tobacco
How CGST/SGST/IGST Appears on Your Invoice
Your invoice must show tax amounts separately — never as a combined "GST" total.
Line Item
Taxable Value
CGST 9%
SGST 9%
Total
Consulting Services
₹50,000
₹4,500
₹4,500
₹59,000
Software Support
₹30,000
₹2,700
₹2,700
₹35,400
Total
₹80,000
₹7,200
₹7,200
₹94,400
ITC Matching: Why Getting CGST/SGST/IGST Right Matters
When you issue a wrong invoice — e.g., charging CGST+SGST on an interstate supply — your buyer cannot correctly claim ITC. The GSTN system matches ITC claims with the supplier's returns. A mismatch triggers notices and the buyer may lose the ITC entirely.
Important
If you charged CGST+SGST on what should have been an IGST invoice, issue a credit note and a fresh corrected invoice. Do not just verbally adjust — the credit note is mandatory under GST law.
FAQs
Can I charge both IGST and CGST+SGST on the same invoice?
No. You charge either CGST+SGST (intrastate) or IGST (interstate) — never both on the same supply.
What determines whether supply is intrastate or interstate?
The place of supply, not the delivery address or billing address. For most services, place of supply is the location of the recipient. For goods, it is where the goods are delivered.
Does IGST go to the state or central government?
IGST is collected by the Central Government and then apportioned to the destination state. This is the mechanism that prevents double taxation between states.
What is UTGST and when do I use it?
UTGST (Union Territory GST) replaces SGST for supplies made within Union Territories like Chandigarh, Dadra & Nagar Haveli, Daman & Diu, Lakshadweep, and Andaman & Nicobar Islands. Delhi and Puducherry have their own legislatures, so they use SGST, not UTGST.
If the GST rate is 18%, how much is CGST and SGST each?
CGST = 9% and SGST = 9%. They always split equally at half the total rate each.
Why Businesses Stop Using Excel for GST Invoices
Manual GST calculation mistakes
One wrong CGST/SGST split or a misapplied rate triggers notices and ITC denial for your buyer.
Slow invoice creation
Copying last month's Excel file, updating dates, recalculating — 20 minutes for what should take 30 seconds.
Formatting breaks on every device
Excel invoices look different on every printer and PDF converter. Clients complain about unreadable layouts.
No easy sharing or payment link
Sending PDFs over WhatsApp with no way for clients to pay directly slows down collections.
Incorrect tax type (IGST vs CGST+SGST)
Excel can't auto-detect intra vs inter-state supply. Wrong tax type = ITC rejected for your buyer.
Disclaimer: The information in this article is for general informational purposes only and does not constitute professional tax, legal, or financial advice. GST rules and rates are subject to change. Consult a qualified CA or tax professional before making compliance decisions.
Create Invoice with Auto GST Calculation — Free
Create professional GST invoices instantly — no Excel, no manual calculations.