Free Online GST Calculator

What is GST and how does it work in India?

GST (Goods and Services Tax) is a value-added tax levied on the supply of most goods and services across India. It replaced a web of indirect taxes with a single, unified system. GST is applied at every stage of the supply chain, but businesses can claim input tax credit on the tax they have already paid, so the final tax is effectively borne by the end consumer.

GST in India has four components: CGST (Central GST), SGST (State GST), IGST (Integrated GST) and UTGST (Union Territory GST). Which one applies depends on whether the transaction happens within a state, between states, or in a union territory.

Types of GST

Intra-state supply (CGST + SGST)

When goods or services are sold within the same state, the GST is split equally between the Centre and the State. For example, an 18% GST on an intra-state sale is charged as 9% CGST + 9% SGST.

Inter-state supply (IGST)

When goods or services move from one state to another, a single Integrated GST (IGST) is charged. The full 18% in the example above would be collected as 18% IGST.

Union territories (UTGST)

For supplies within a union territory, UTGST replaces SGST and is charged alongside CGST.

Inclusive vs Exclusive GST

Exclusive GST means the amount you enter is the base price, and GST is added on top of it. This is the most common way prices are quoted in business-to-business invoicing.

Inclusive GST means the amount you enter already contains GST. The calculator works backwards to separate the base price from the tax that is bundled inside the total — useful for retail prices that are shown tax-inclusive.

How to calculate GST

The core formula for exclusive GST is:

GST Amount = (Original Cost × GST%) / 100

For example, on a base amount of ₹2,000 at a 5% GST rate, the GST is (2,000 × 5) / 100 = ₹100, making the total ₹2,100.

Benefits of using a GST calculator

• Time-saving: Get instant results without manual maths or spreadsheets.
• Accuracy: Eliminate rounding errors and avoid miscalculations that lead to compliance issues.
• Business efficiency: Quote prices, prepare invoices and plan margins faster, so you can focus on growing your business.