GST (Goods and Services Tax) is an indirect tax levied on the supply of goods and services. Understanding GST calculation is essential for businesses and consumers.
What is GST?
GST is a comprehensive, multi-stage, destination-based tax that is levied on every value addition. In India, GST replaced many indirect taxes like VAT, Service Tax, Excise Duty, etc.
Components of GST
- CGST (Central GST): Levied by Central Government on intra-state supplies
- SGST (State GST): Levied by State Government on intra-state supplies
- IGST (Integrated GST): Levied by Central Government on inter-state supplies
GST Slab Rates in India (2026)
| GST Rate | Items |
|---|---|
| 0% (Nil) | Fresh fruits, vegetables, milk, eggs, education services |
| 5% | Packaged food, tea, coffee, spices, fertilizers |
| 12% | Computers, processed food, butter, ghee, mobile phones |
| 18% | IT services, hair oil, toothpaste, soaps, capital goods |
| 28% | Luxury cars, cigarettes, aerated drinks, cement |
GST Calculation Formulas
1. Adding GST to Base Price (GST Inclusive)
Net Price = Original Cost + GST Amount
Example: Product price ₹1000, GST 18%
- GST = 1000 × 18/100 = ₹180
- Final Price = 1000 + 180 = ₹1,180
2. Removing GST from Total Price (GST Exclusive)
GST Amount = Total Price - Original Price
Example: Total price ₹1,180 with 18% GST
- Original = (1180 × 100) / (100 + 18) = 118000/118 = ₹1,000
- GST = 1180 - 1000 = ₹180
CGST/SGST vs IGST Calculation
Intra-State Sale (Within same state)
If GST rate is 18% (CGST 9% + SGST 9%) on ₹10,000:
- CGST = 10,000 × 9/100 = ₹900
- SGST = 10,000 × 9/100 = ₹900
- Total Tax = ₹1,800
Inter-State Sale (Different states)
If IGST rate is 18% on ₹10,000:
- IGST = 10,000 × 18/100 = ₹1,800
- Total Tax = ₹1,800 (collected by Central)
Calculate GST Instantly
Use our free GST Calculator for quick and accurate calculations.
Try GST CalculatorReverse Charge Mechanism (RCM)
Under RCM, the recipient pays GST directly to government instead of supplier. Applicable for:
- Services from unregistered dealers
- Specified goods/services (like legal services by advocate)
- E-commerce operators
GST Composition Scheme
For small businesses (turnover up to ₹1.5 crore):
- Pay GST at fixed rate (1% manufacturers, 5% restaurants, 6% others)
- File quarterly returns (instead of monthly)
- Cannot claim input tax credit
Input Tax Credit (ITC)
Businesses can claim credit for GST paid on purchases. Example:
- You buy raw material @ 18% GST: Pay ₹180
- You sell finished product @ 18% GST: Collect ₹180
- Net GST payable = ₹180 - ₹180 = ₹0
GST Return Filing
- GSTR-1: Monthly (Outward supplies)
- GSTR-3B: Monthly (Summary return + payment)
- GSTR-9: Annual return
- CMP-08: Quarterly for composition scheme
Common Mistakes to Avoid
- ❌ Wrong HSN/SAC codes
- ❌ Missing invoice details in GSTR-1
- ❌ Not claiming eligible ITC
- ❌ Late filing (penalty ₹50-200 per day)
- ❌ Mixing up CGST/SGST with IGST
FAQs
Q: What is the minimum turnover for GST registration?
A: ₹20 lakh (₹10 lakh for special category states) for goods. ₹20 lakh for services.
Q: Can I claim ITC on GST paid for car?
A: Generally no, unless used for transportation business.
Q: What is the penalty for not filing GST returns?
A: Late fee ₹50 per day (₹25 each for CGST & SGST). Maximum ₹5,000.
Q: Is GST applicable on exports?
A: Exports are zero-rated (no GST) but you can claim refund of input tax credit.
Q: How to calculate GST on MRP?
A: MRP is inclusive of GST. Use reverse calculation formula: Base Price = MRP × 100/(100+GST%)
