GST Calculator — Calculate GST Amount Instantly

Add or remove GST at any Indian tax slab. See CGST, SGST split and total price instantly.

Last updated: March 2026

How to Use This GST Calculator

This free online GST calculator helps you compute the Goods and Services Tax for any amount under India's GST regime. Whether you are a business owner generating invoices, a freelancer pricing services, or a consumer verifying a bill, follow these steps:

  1. Enter the Amount — Type the base price (before GST) or the total price (including GST) depending on what you already know. For example, enter 10,000 if that is your product cost.
  2. Select the GST Rate — Choose the applicable GST slab from the dropdown: 3%, 5%, 12%, 18% or 28%. Most services and electronics fall under 18%, while luxury goods attract 28%.
  3. Choose the Calculation Type — Select "Add GST to amount" if you have the base price and want the final inclusive price. Select "Remove GST from amount" if you have the GST-inclusive price and want to find the original cost and tax component.
  4. View Your Results — The calculator instantly displays the original price, total GST amount, CGST and SGST split, and the total payable amount. Results update automatically whenever you change any input.

GST Rate Categories in India

India's GST structure uses multiple rate slabs to balance revenue collection with the affordability of essential goods. Here is a comprehensive breakdown of each slab with common examples:

GST RateCategoryExamples
0%Exempt / EssentialFresh fruits, vegetables, milk, eggs, bread, salt, natural honey, educational services, healthcare services
3%Precious MetalsGold, silver, platinum, diamonds, gold jewellery, silver ornaments
5%NecessitiesPackaged food items, sugar, tea, coffee, edible oils, economy class air tickets, footwear below ₹500, fertilisers, newspapers
12%Standard (Lower)Processed food, butter, ghee, fruit juices, apparel above ₹1,000, business class air tickets, mobile phones, sewing machines
18%StandardMost goods and services — electronics, computers, refrigerators, restaurant meals (AC), IT services, financial services, telecom, hair oil, toothpaste, steel products
28%Luxury / DemeritAutomobiles, cement, chocolates, pan masala, tobacco products, aerated drinks, washing machines, air conditioners, dishwashers, paint

Note: Some items under the 28% slab also attract an additional GST compensation cess. For instance, luxury cars may have a cess of 1% to 22% on top of the 28% GST, and aerated drinks carry a 12% cess.

How GST Works in India

The Goods and Services Tax (GST) was introduced on 1 July 2017, replacing a complex web of central and state indirect taxes including excise duty, service tax, VAT, CST, entertainment tax and octroi. It is a comprehensive, multi-stage, destination-based tax levied on every value addition in the supply chain.

The key principle behind GST is the input tax credit (ITC) mechanism. Each business in the supply chain pays GST on its purchases and collects GST on its sales. The tax already paid on inputs is credited against the tax collected on outputs. This eliminates the cascading effect (tax on tax) that plagued the earlier system.

GST Calculation Formulas

Add GST: Total = Amount + (Amount × Rate / 100)
Remove GST: Original = Amount × 100 / (100 + Rate)

For intra-state sales, the GST is split equally into CGST (Central GST) and SGST (State GST). So if 18% GST applies, 9% goes as CGST and 9% as SGST. For inter-state sales, the full rate is charged as IGST (Integrated GST).

CGST vs SGST vs IGST — Key Differences

Understanding the three components of GST is essential for correct invoicing and tax filing in India:

ComponentFull FormWhen AppliedCollected By
CGSTCentral GSTIntra-state (within same state)Central Government
SGSTState GSTIntra-state (within same state)State Government
IGSTIntegrated GSTInter-state (between two states) or importsCentral Government (later shared with destination state)

For example, if a seller in Maharashtra sells goods worth ₹10,000 to a buyer also in Maharashtra at 18% GST, the invoice will show ₹900 CGST + ₹900 SGST = ₹1,800 GST. If the same seller sells to a buyer in Karnataka, the invoice will show ₹1,800 IGST instead. In Union Territories, UTGST replaces SGST.

Input tax credit can be utilised across these components with specific rules: IGST credit can be used against IGST, CGST and SGST liabilities. CGST credit can be used against CGST and then IGST. SGST credit can be used against SGST and then IGST. CGST credit cannot be used against SGST and vice versa.

Frequently Asked Questions

What are the current GST rates in India?

India has five main GST rate slabs: 0% for essential items like fresh fruits, vegetables and milk; 3% for gold and silver; 5% for household necessities like packaged food and economy rail tickets; 12% for processed food and business class air tickets; 18% for most goods and services including electronics, IT services and financial services; and 28% for luxury and demerit goods such as automobiles, cement, tobacco and aerated drinks. Some items also attract an additional compensation cess above the 28% slab.

What is the difference between CGST, SGST and IGST?

CGST (Central GST) and SGST (State GST) are levied equally on intra-state transactions. For instance, if the GST rate is 18%, then 9% CGST goes to the Central Government and 9% SGST goes to the State Government. IGST (Integrated GST) applies on inter-state transactions and imports at the full rate. The Central Government collects IGST and then distributes the state portion to the destination state. This split ensures both central and state governments receive their share of tax revenue.

What is the reverse charge mechanism under GST?

Under the reverse charge mechanism (RCM), the liability to pay GST shifts from the supplier to the recipient of goods or services. This applies in specific cases notified by the government under Sections 9(3) and 9(4) of the CGST Act, such as services received from an unregistered dealer, legal services from an advocate, services by a goods transport agency (GTA), or sponsorship services. The recipient must self-assess and pay the GST directly to the government and can later claim input tax credit on it.

What are HSN codes and why are they important for GST?

HSN stands for Harmonized System of Nomenclature, an internationally standardised system of names and numbers to classify traded goods. Under India's GST, businesses with annual turnover above ₹5 crore must mention 6-digit HSN codes on all invoices. Businesses with turnover between ₹1.5 crore and ₹5 crore need 4-digit HSN codes. HSN codes determine the applicable GST rate for each product and are essential for correct tax computation, filing returns on the GST portal, and enabling the government to track taxable goods systematically.

What is the composition scheme under GST?

The composition scheme is a simplified tax scheme for small businesses with annual turnover up to ₹1.5 crore (₹75 lakh for special category states). Under this scheme, businesses pay GST at a flat rate: 1% for manufacturers, 5% for restaurant services, and 1% for other suppliers. They file quarterly returns instead of monthly ones and face lower compliance burden. However, composition dealers cannot claim input tax credit, cannot make inter-state supplies, and must mention "composition taxable person" on their invoices and signboards.

How do I calculate GST on an amount that already includes GST?

To extract GST from an inclusive amount (reverse calculation), use the formula: Original Price = GST-inclusive Amount × 100 / (100 + GST Rate). For example, if the total bill is ₹11,800 and the GST rate is 18%, then Original Price = 11,800 × 100 / 118 = ₹10,000, and GST = ₹11,800 − ₹10,000 = ₹1,800 (split as ₹900 CGST + ₹900 SGST for intra-state). You can use this calculator's "Remove GST from amount" option to do this instantly.

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