GST Calculator India — CGST, SGST & IGST Split Calculator
CGST · SGST · IGST Breakdown — Invoice, Reverse GST & Business Summary
Understanding the CGST/SGST/IGST split is essential for B2B businesses and GST return filing. When you buy from a supplier in the same state, input tax credit is CGST + SGST. When you buy from another state, it's IGST. Wrong categorization leads to GST notice. This calculator automatically determines the correct split based on your supply type (intra-state vs inter-state) and applicable rate.
🧾 GST Calculator
How to Use GST Calculator India
Enter the base amount, select the GST rate slab (5%, 12%, 18%, 28%), choose Exclusive (add GST to amount) or Inclusive (extract GST from total), and select whether it's an Intra-state (CGST + SGST) or Inter-state (IGST) transaction. Get instant breakup — no login, no install.
How GST Calculator Works — Formula
GST Exclusive: GST Amount = Base × Rate/100 · Total = Base + GST
GST Inclusive (Reverse): Base = Total ÷ (1 + Rate/100) · GST = Total − Base
CGST & SGST = GST Amount ÷ 2 each (for intra-state transactions).
Example: ₹10,000 base at 18% → GST = ₹1,800 · CGST = ₹900 · SGST = ₹900 · Total = ₹11,800.
CGST vs SGST vs IGST — What's the Difference?
CGST (Central GST) goes to Central Government. SGST (State GST) goes to State Government. Both are charged on intra-state transactions (seller and buyer in the same state), each at half the total GST rate. IGST (Integrated GST) is charged on inter-state transactions and goes entirely to the Central Government, which then distributes to the destination state.
Real-Life GST Examples India 2025
🛒 Grocery (Milk, fresh vegetables): 0% GST — exempt essentials.
💊 Medicines, life-saving drugs: 5% GST — reduced rate for healthcare.
📱 Mobile phones, computers: 12% GST — standard electronics rate.
🍕 Restaurant services, AC restaurants: 5% or 18% GST — varies by type.
🏠 Under-construction flats: 5% GST (affordable) or 12% (premium).
🚗 Luxury cars: 28% GST + 12–22% Cess — highest tax bracket.
Frequently Asked Questions
How to calculate CGST and SGST separately?
For intra-state (same state): CGST = taxable value × (GST rate ÷ 2) ÷ 100. SGST = same as CGST. For 18% GST on ₹10,000: CGST = ₹10,000 × 9% = ₹900. SGST = ₹10,000 × 9% = ₹900. Total GST = ₹1,800. Invoice total = ₹11,800. Never add CGST and SGST rates — both together make total GST rate.
What is Input Tax Credit (ITC) in GST?
ITC = GST paid on purchases that can be set off against GST collected on sales. Example: buy raw material paying ₹18,000 GST, sell finished goods collecting ₹30,000 GST. You pay only ₹30,000 − ₹18,000 = ₹12,000 to government. ITC makes GST a value-added tax — you're taxed only on your value addition, not entire selling price.
What is reverse charge mechanism in GST?
Normally seller charges GST. Under Reverse Charge Mechanism (RCM), BUYER pays GST directly to government. Applies to: goods from unregistered dealers, services from specific categories (advocate, GTA transport, rent from unregistered landlord). Buyer can claim ITC on RCM GST paid if used for business.
How to file GST returns for small businesses?
GSTR-1: outward supply details (monthly if turnover >₹5Cr, quarterly if less). GSTR-3B: monthly summary return with tax payment. GSTR-9: annual consolidated return. Under composition scheme: GSTR-CMP-08 quarterly + GSTR-4 annual. Due dates: GSTR-1 by 11th, GSTR-3B by 20th of following month.