India's Goods and Services Tax (GST) simplified the old tax system into one. Understanding how to calculate it is crucial for your business's financial health and compliance in 2026. This guide breaks down the formulas and rules for you.
The Four Pillars of GST
GST is divided into four main types depending on the transaction. CGST and SGST are for sales within a state, while IGST is for sales between states. UTGST is a special tax that replaces SGST in certain Union Territories.
Intra-State vs. Inter-State
The type of GST applied depends on geography. An intra-state transaction happens within the same state (e.g., from Mumbai to Pune). An inter-state transaction crosses state lines (e.g., from Maharashtra to Gujarat).
How Intra-State Tax Works
If you sell goods worth ₹10,000 within Maharashtra at an 18% GST rate, the tax is split. You will collect 9% as CGST (₹900) for the Central government and 9% as SGST (₹900) for the State government.
How Inter-State Tax Works
Now, sell the same ₹10,000 goods from Maharashtra to Gujarat. The entire 18% tax, or ₹1,800, is collected as IGST. This single tax is levied by the Central Government and later shared with the destination state.
The 2026 GST Rate Slabs
For 2026, the GST Council has set five primary tax slabs for all goods and services. These rates are determined by the product's category, from essential items to luxury goods. The main slabs are 0%, 5%, 12%, 18%, and 28%.
Essentials & Necessities
The 0% slab applies to essential food items like fresh milk and books, keeping them tax-free. The 5% slab covers household necessities such as sugar, tea, and basic packaged foods, making them affordable for everyone.
Standard & Luxury Goods
The 18% rate is standard for most goods and services, including IT services, electronics, and capital goods. The highest 28% slab is for luxury and 'sin' goods like premium cars, air conditioners, and aerated drinks.
The Basic Calculation
To find the final price, add the GST amount to the original cost. Use the formula: GST Amount = (Original Cost x GST Rate) / 100. The final price is simply the Original Cost plus the calculated GST Amount.