Free Online GST Calculator India (2026)
Calculate GST Inclusive & Exclusive amounts, CGST, SGST, and IGST splits across all tax slabs (0%, 5%, 12%, 18%, 28%, 40% & custom rates) in real-time.
Understanding the GST 2.0 Slabs Structure
Under India's latest GST rationalization framework, tax classifications have been consolidated into three primary standard tiers: 5% for essential everyday items, 18% as the broad standard rate covering most commercial services, software, design, and manufacturing, and 40% for luxury items and demerit goods. Special concession slabs of 0% (unprocessed food, basic healthcare SAC 9993) and 3% (precious jewelry) remain applicable.
How to Calculate GST in India: Formulas Explained
1. Forward GST Calculation (Exclusive)
Use this when you know your net selling price and need to add GST for the customer:
Total Invoice = Base Price + GST Amount
Example: ₹10,000 base at 18% GST = ₹1,800 tax. Total = ₹11,800.
2. Reverse GST Calculation (Inclusive)
Use this when the MRP or total received amount already includes GST:
GST Amount = Total Amount − Base Price
Example: ₹11,800 total at 18% GST = ₹10,000 base + ₹1,800 GST.
When to Apply CGST + SGST vs IGST
Intra-State (Same State) Sale
When the supplier's registered location and the buyer's place of supply are in the same state (e.g. Mumbai seller to Pune buyer). The total GST is divided into 50% CGST (Central Government) and 50% SGST (State Government).
Inter-State (Different State) Sale
When the supplier's location and the buyer's place of supply are in different states or union territories (e.g. Bangalore seller to Delhi buyer). The full 100% tax is levied as Integrated GST (IGST).
GST Calculation FAQs
How is GST calculated in India (GST Formula)?
For GST Exclusive amounts (adding tax): GST Amount = (Base Amount × GST Rate) / 100, Total = Base Amount + GST Amount. For GST Inclusive amounts (removing tax): Base Amount = Total Amount / (1 + (GST Rate / 100)), GST Amount = Total Amount − Base Amount.
What is the difference between CGST, SGST, and IGST?
CGST (Central GST) and SGST (State GST) are applied on Intra-State transactions (buyer and seller in the same state) where the total tax is split equally 50/50 between Central and State governments. IGST (Integrated GST) is applied on Inter-State transactions (buyer and seller in different states) where 100% of the tax goes to the Central government for redistribution.
What are the latest GST tax slabs under GST 2.0?
Under the GST 2.0 rationalization reforms, the primary standard slabs are 5% (essential goods/mass consumption), 18% (standard rate for most services, IT, consulting, and manufactured goods), and 40% (sin goods, luxury automobiles, aerated drinks, tobacco). Special rates include 0% (exempt essential food/healthcare) and 3% (gold, silver, precious jewelry).
Can I use this calculator for both Goods (HSN) and Services (SAC)?
Yes! The GST mathematical formula is identical for goods and services. Simply select or input the applicable GST slab (e.g., 18% for IT/consulting SAC 9983, 5% for apparel, 0% for healthcare SAC 9993) to see exact tax splits.
What is Input Tax Credit (ITC) under GST?
Input Tax Credit (ITC) allows GST-registered businesses to reduce the tax they have already paid on purchases (inputs) from the tax they collect on sales (output tax), preventing cascading tax-on-tax effects.
How do I create a compliant GST invoice after calculating tax?
Click the 'Create Invoice with this Rate' button on this page. It will automatically load the BillBanao invoice builder where you can add your company GSTIN, client GSTIN, HSN/SAC codes, and download a compliant PDF tax invoice.