GST Calculator

GST (Goods and Services Tax) is a destination-based indirect tax on the supply of goods and services in India. This calculator adds GST to a base amount or works backwards to find the base and tax from a GST-inclusive price.

Choose the rate, whether you are adding or removing GST, and the type of supply.

Assumptions used

Compensation cess (on some 28% items) is not included.
Rates shown are the common slabs; the GST Council notifies the applicable rate per HSN/SAC.

Enter your details

Results

Total (incl. GST)

₹11,800

Base Amount: ₹10,000
GST Amount: ₹1,800
CGST: ₹900
SGST: ₹900
IGST: ₹0

Base amount₹10.0 K(85%)
GST₹1.8 K(15%)

GST formulas

Adding GST: GST = Base × Rate ÷ 100 ; Total = Base + GST

Removing GST: Base = Total ÷ (1 + Rate ÷ 100) ; GST = Total − Base

For an intra-state supply the GST is split equally into CGST (central) and SGST (state). For an inter-state supply it is a single IGST at the full rate.

Worked example

Base amount ₹10,000 at 18%, intra-state.
GST = 10,000 × 18 ÷ 100 = ₹1,800.
CGST = SGST = ₹900 each. Total invoice = ₹11,800.
Reverse: from ₹11,800 inclusive, Base = 11,800 ÷ 1.18 = ₹10,000; GST = ₹1,800.

Common GST rate slabs

Rates and classifications are set by the GST Council and change from time to time — verify the current rate for your HSN/SAC code.
Slab	Typical goods / services
0% / exempt	Fresh produce, most unbranded food grains, some services
5%	Essential items, economy transport, small restaurants
12%	Processed foods, business-class air travel, some appliances
18%	Most goods and services, standard rate
28%	Luxury and 'sin' goods; a compensation cess may also apply

Who charges GST?

A business must register for GST once turnover crosses the threshold (or immediately for inter-state supply and certain categories). Registered businesses collect GST on sales and claim input tax credit on eligible purchases.

Rates & rules: As on 2025. Source: GST Council rate notifications. GST rates and item classifications change periodically. Confirm the current rate for your HSN/SAC code.

This calculator is for education and illustration only. Results are estimates based on the inputs and assumptions shown and are not financial, investment, tax or legal advice. Verify figures with your bank, a registered adviser or the relevant government department before acting.

Frequently asked questions

How do I remove GST from a total amount?

Divide the GST-inclusive amount by (1 + rate/100). For 18%, divide by 1.18 to get the base; the difference is the GST. Select 'Remove GST' in the calculator to do this automatically.

What is the difference between CGST, SGST and IGST?

For supplies within a state, GST splits into CGST (to the Centre) and SGST (to the state), each half the rate. For supplies between states, a single IGST at the full rate is charged.

Which GST rate applies to my product?

It depends on the HSN code for goods or SAC code for services, as notified by the GST Council. 18% is the most common standard rate. Check the current notification for your category.

Is GST calculated before or after discount?

GST is charged on the transaction value after any discount shown on the invoice at the time of supply. Post-sale discounts have separate treatment.

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