Free GST Calculator
Add GST to a price or work out the GST inside an inclusive amount.
Informational only. This calculator performs arithmetic on the rate you enter. GST rates depend on the goods or services, their classification and current government notifications — confirm the applicable rate with the official GST portal or a tax professional. This is not tax advice.
How it works
- Choose Add GST (price before tax) or Remove GST (price including tax).
- Enter the amount and pick or type the GST rate.
- Select within-state or between-states supply.
- Read the net amount, GST, gross amount and the CGST/SGST or IGST split.
Frequently asked questions
How do I add GST to a price?
Multiply the price by the rate and divide by 100, then add it. For example, 18% GST on ₹1,000 is ₹180, so the total is ₹1,180.
How do I remove GST from an inclusive price?
Divide the inclusive amount by (1 + rate / 100). For ₹1,180 at 18%, the net price is 1,180 / 1.18 = ₹1,000 and the GST is ₹180. Simply taking 18% of ₹1,180 would be wrong.
What is the difference between CGST, SGST and IGST?
For sales within one state, GST is split equally into Central GST and State GST (for example 9% + 9% for 18%). For sales between states, the full rate is charged as Integrated GST (IGST).
Which GST rate applies to my product?
Rates depend on the HSN/SAC classification of the goods or service and change through government notifications. Most items now fall under the 5% or 18% slabs, with 40% for some luxury and sin goods — always confirm on the official GST portal.
Add or remove GST in seconds
Whether you are preparing an invoice, checking a bill or pricing a product, you often need to know the GST inside a price or the price after GST. This calculator handles both directions and shows how the tax splits between the central and state governments.
GST formulas
- Adding GST: GST = net × rate ÷ 100; gross = net + GST.
- Removing GST: net = gross × 100 ÷ (100 + rate); GST = gross − net.
A common mistake is to take 18% of an inclusive price to find the tax. That overstates it — 18% of ₹1,180 is ₹212.40, but the actual GST inside ₹1,180 is ₹180.
CGST, SGST and IGST
For an intra-state supply the GST is shared equally: at 18%, 9% is CGST and 9% is SGST (or UTGST in union territories). For an inter-state supply the whole 18% is charged as IGST. The total tax is the same either way.
GST rate slabs
Since the GST rationalisation that took effect on 22 September 2025, most goods and services fall under the 5% and 18% slabs, with a 40% rate for selected luxury and sin goods. Special rates such as 0.25% and 3% apply to rough diamonds and precious metals. Always confirm the rate for your HSN or SAC code.