What is a GST calculator?
To add GST, multiply the base price by (1 + rate ÷ 100). To remove GST from an inclusive price, divide it by (1 + rate ÷ 100). Inside one state the tax is split equally into CGST and SGST; between states it is charged as IGST.
Features
- Add GST or remove GST
- CGST + SGST or IGST breakdown
- Any rate, with one-tap common slabs
- Copy the breakdown for a quote or message
How to use the GST calculator
- Choose Add GST or Remove GST.
- Enter the amount.
- Tap a rate or type your own.
- Choose within a state or between states, and read the breakdown.
GST formulas
| You know | Formula | Example at 18% |
|---|---|---|
| Price before GST | GST = price × rate ÷ 100 | ₹1,000 → GST ₹180, total ₹1,180 |
| Price including GST | Base = price ÷ (1 + rate ÷ 100) | ₹1,180 → base ₹1,000, GST ₹180 |
| Sale within a state | CGST = SGST = GST ÷ 2 | CGST ₹90 + SGST ₹90 |
| Sale to another state | IGST = full GST | IGST ₹180 |
A common mistake is removing GST by subtracting 18% of the inclusive price: 18% of ₹1,180 is ₹212.40, not the ₹180 actually included.
GST rate slabs since September 2025
From 22 September 2025 the GST Council moved most goods and services to two main slabs, 5% and 18%, with 40% for a short list of luxury and sin goods. Some items keep special rates, such as 3% on gold and 0.25% on rough diamonds, and many essentials are exempt. Rates are set per HSN/SAC code, so confirm yours on the official GST rate finder before invoicing.
Frequently asked questions
How do I calculate 18% GST on ₹1,000?
Multiply ₹1,000 by 18 and divide by 100: GST is ₹180, so the total is ₹1,180. Within a state that is ₹90 CGST and ₹90 SGST.
How do I remove 18% GST from a price?
Divide the price by 1.18. For ₹1,180 the base is ₹1,000 and the GST included is ₹180.
When is IGST charged instead of CGST and SGST?
IGST applies when the supplier's location and the place of supply are in different states or union territories, and on imports. Within the same state, CGST and SGST apply.
Is the result legally binding?
No. It is arithmetic on the rate you enter. Your accountant or the GST portal confirms which rate applies to your goods or services.
Can I use it for GST in Australia, New Zealand or Canada?
The arithmetic is the same, but the CGST and SGST split is Indian only. The VAT calculator does the same sums in your own currency without the split: type 10% for Australia or 15% for New Zealand.
Last updated 15 November 2026. Made by Criza Labs. Spotted a mistake? Tell us.
