GST Calculator India
Calculate GST at the current 0%, 5%, 18% and 40% slabs (GST 2.0, effective 22 September 2025). Find price with GST and without GST instantly.
About this calculator
This GST calculator adds GST to a price or removes it from a GST-inclusive price, and splits the tax into CGST and SGST. It uses the rate structure that has applied since the GST rate rationalisation of 22 September 2025: 5% for essentials, 18% as the standard rate and 40% for luxury and sin goods, with 0% for nil-rated items and a special 3% for gold and silver.
The old 12% and 28% slabs are still in the rate list because invoices raised before the change, and some legacy accounting work, still use them. Pick the rate shown on your invoice or the HSN schedule. The calculator never guesses the rate for a product, since that depends on its HSN code.
How to use it
- Enter the Amount in rupees.
- Choose the GST Rate. Use 18% if you are not sure and check the HSN schedule afterwards.
- Choose the Amount Type: Excluding GST to add tax on top, or Including GST to take the tax out of a final price.
- Press Calculate GST to see the base amount, total GST, the CGST and SGST halves, and the final total.
GST formulas
To add GST: GST = Base × Rate ÷ 100 and Total = Base + GST. To remove GST from a price that already includes it: Base = Total × 100 ÷ (100 + Rate) and GST = Total − Base. For a sale within one state the GST splits equally into CGST and SGST. For a sale between states the whole amount is IGST, which equals CGST + SGST.
Worked example
₹10,000 at 18%, GST added on top
| Base amount | ₹10,000 |
| GST at 18% | ₹1,800 |
| CGST (9%) | ₹900 |
| SGST (9%) | ₹900 |
| Total invoice value | ₹11,800 |
Going the other way, a final price of ₹11,800 that includes 18% GST contains ₹10,000 of base value and ₹1,800 of tax. A common mistake is to take 18% off ₹11,800, which gives ₹2,124 and is wrong.
Tips and common mistakes
- Never subtract the percentage from a GST-inclusive price. Divide by 1 plus the rate instead.
- Intra-state sales carry CGST plus SGST. Inter-state sales carry IGST at the combined rate.
- The rate depends on the HSN or SAC code, not on how the product is described. Check the code on the GST portal before you invoice.
- Round GST per invoice line consistently so your return matches your books.
- Keep invoices raised before 22 September 2025 at the rate that applied on the invoice date.
Frequently asked questions
What are the GST rates now?
Since 22 September 2025 the main slabs are 5% and 18%, with 40% on luxury and sin goods, 0% on exempt or nil-rated items and 3% on gold and silver. The 12% and 28% slabs were retired for most goods.
How do I calculate GST from an inclusive price?
Divide the price by 1 plus the rate as a decimal. At 18% divide by 1.18. The difference between the price and the result is the GST.
What is the difference between CGST, SGST and IGST?
CGST goes to the Centre and SGST to the state for sales inside one state, each at half the rate. IGST is charged on sales between states and goes to the Centre, which shares it with the destination state.
Can I claim input tax credit?
Registered businesses can claim credit for GST paid on business inputs, subject to conditions such as a valid invoice and the supplier filing returns. This calculator only works out the tax on one amount.
Does GST apply to every business?
No. Registration is mandatory above the turnover threshold for your state and type of supply, and some goods and services are exempt.
Is this calculator suitable for filing returns?
It is for quick estimates and invoice checks. File your returns from your accounting records and the GST portal.