How does the GST calculator work?
There are two kinds of GST calculation. If you have a price before GST and need to raise an invoice, GST is added to it. If you have a bill that already includes GST, the calculator separates the GST from the base price.
Adding GST (exclusive price)GST = Amount × Rate ÷ 100 · Total = Amount + GST
Removing GST (inclusive price)Base price = Total ÷ (1 + Rate ÷ 100) · GST = Total − Base price
Example: GST on ₹10,000
| GST rate | GST amount | Total bill | GST inside a ₹10,000 bill |
|---|---|---|---|
| 5% | ₹500 | ₹10,500 | ₹476.19 |
| 18% | ₹1,800 | ₹11,800 | ₹1,525.42 |
| 40% | ₹4,000 | ₹14,000 | ₹2,857.14 |
GST rates in 2026 (after GST 2.0)
From 22 September 2025, GST moved to a simpler structure. The 12% and 28% slabs were removed: most items at 12% moved to 5%, and most items at 28% moved to 18%. A new 40% rate applies to luxury and sin goods.
| Rate | Common examples |
|---|---|
| 0% (nil) | Fresh fruits and vegetables, milk, eggs, unpacked grains, education, most healthcare, individual life and health insurance |
| 0.25% | Rough diamonds |
| 3% | Gold, silver and jewellery (making charges are taxed separately) |
| 5% | Packaged food staples, edible oils, medicines, many household goods, small restaurants |
| 18% | Standard rate: electronics, appliances, most cars, professional services (CA, legal, consulting), telecom |
| 40% | Tobacco, pan masala, aerated and sugary drinks, luxury cars |
Check before you invoice: the GST Council revises item rates from time to time. Confirm the rate for your product or service using its HSN or SAC code.
CGST, SGST and IGST explained
- Sale within the same state: GST is split equally into CGST (Centre) and SGST (State). For example, 18% becomes 9% CGST + 9% SGST.
- Sale to another state: the full GST is charged as IGST. For example, 18% IGST.
- In a Union Territory without a legislature, UTGST replaces SGST.
When is GST registration required?
A business supplying goods must register once its annual turnover crosses ₹40 lakh (₹20 lakh in some states). For services, the limit is ₹20 lakh (₹10 lakh in some states). Registration is required regardless of turnover in some cases, such as inter-state supply of goods or selling through e-commerce platforms.
Frequently asked questions
How do you calculate GST?
GST = Amount × GST rate ÷ 100. For example, 18% GST on ₹10,000 is ₹1,800, so the total bill is ₹11,800.
How do I remove GST from a bill amount?
Base price = Total ÷ (1 + rate ÷ 100). For an ₹11,800 bill at 18% GST, the base price is 11,800 ÷ 1.18 = ₹10,000 and the GST is ₹1,800.
What are the GST slabs in 2026?
After GST 2.0, the main slabs are 0%, 5%, 18% and 40%. Gold and jewellery attract 3% and rough diamonds 0.25%. The 12% and 28% slabs have been removed.
When is CGST and SGST charged instead of IGST?
CGST and SGST are charged in equal halves when the supplier and the buyer are in the same state. IGST is charged on supplies from one state to another.
What is the GST rate on professional services?
Most professional and consulting services, such as CA, legal and advisory services, attract 18% GST. Some legal services fall under reverse charge, where the client pays the GST.
Can I charge GST without GST registration?
No. A business must have a GSTIN before it can charge GST on its invoices.
How much tax is paid under the composition scheme?
Small businesses under the composition scheme pay a fixed rate on turnover (for example, 1% for traders) and cannot charge GST to customers. Speak to an expert to check eligibility.
Is this GST calculator free?
Yes. It is free and needs no sign-up. The results are estimates, so confirm the rate before filing.