Free GST Calculator India
Add GST to a price or extract GST from a total. CGST/SGST automatically split for intra-state; IGST for inter-state.
The formula
How GST is calculated in India
GST in India is a destination-based tax. The formula is straightforward: GST Amount = Taxable Value × (GST Rate ÷ 100). The total payable is the taxable value plus the GST amount.
What makes Indian GST unique is the three-way split. For intra-state supply (supplier and buyer in the same state), the GST is divided equally between the Central Government (CGST) and the State Government (SGST). An 18% GST rate becomes 9% CGST + 9% SGST.
For inter-state supply (different states), the full rate is charged as IGST (Integrated GST) collected by the Centre, which later shares the state's portion with the destination state. The split is based on the place of supply — not the billing address.
Add GST (exclusive)
GST = Base Price × Rate / 100
Total = Base Price + GST
CGST = SGST = GST / 2 (intra-state)Remove GST (inclusive)
Base = Total / (1 + Rate / 100)
GST = Total − Base
CGST = SGST = GST / 2 (intra-state)Rate guide
GST rates quick reference
Essential goods — packaged food, medicine, domestic LPG, economy hotel rooms, transport (rail/road)
Processed food, apparel below ₹1,000, business class air travel, work contracts for affordable housing
Most services (IT, consulting, advertising, telecom), computers, electronic items, restaurant meals
Luxury goods, automobiles, tobacco, aerated drinks, casinos, multiplexes. Often + Cess
A 0% rate applies to exempt supplies (fresh produce, most grains, health services). Always verify the rate for your specific HSN/SAC code at cbic-gst.gov.in.
FAQ
Frequently asked questions
How is GST calculated in India?+
GST = Taxable Value × GST Rate ÷ 100. For intra-state supply, the amount is split equally into CGST and SGST (e.g. 18% GST = 9% CGST + 9% SGST). For inter-state supply, the full rate is charged as IGST (e.g. 18% GST = 18% IGST). The split is based on the place of supply, not the billing address.
What is the difference between CGST, SGST, and IGST?+
CGST (Central GST) and SGST (State GST) together make up intra-state GST — each takes half the rate. IGST (Integrated GST) applies to inter-state supply and is collected centrally, then shared with the destination state. Which one applies depends on whether the supplier and buyer are in the same state.
What are the GST rates in India?+
The main GST rates are 5%, 12%, 18%, and 28%. Additionally, 0% applies to exempt goods (fresh produce, most grains), and a special 0.25% rate exists for rough diamonds. Most services fall under 18%. A small number of luxury/demerit goods attract a 28% rate plus an additional Cess.
How do I calculate GST when the price already includes GST?+
Use the reverse GST formula: Taxable Value = Gross Price ÷ (1 + GST Rate ÷ 100). Then GST = Gross Price − Taxable Value. Our calculator's "GST included in price" mode does this automatically.
Is this GST calculator free?+
Yes, completely free with no sign-up. Calculate as many times as you need. To generate a proper GST invoice based on your calculation, use the ZapInvoice invoice builder — also free.
Do I need to charge CGST/SGST or IGST on my invoice?+
If your business (supplier) and the customer (recipient) are in the same state, charge CGST + SGST. If they are in different states, charge IGST. The place of supply rule (not the billing address) determines which applies. ZapInvoice's invoice builder auto-splits based on the state codes you enter.
Skip the manual calculation
Generate your GST invoice with the split done for you
CGST/SGST/IGST split automatically based on place of supply. No manual calculation — ever.
Related