Calculate GST like a serious finance desk.

What is GST?

GST stands for Goods and Services Tax. It is an indirect tax used in India on the supply of goods and services. For businesses, GST affects pricing, invoices, input tax credit, ecommerce listings, agency retainers, freelance invoices, and customer-facing final prices.

How GST is Calculated

GST is calculated by applying the relevant GST rate to the taxable value. If a product has a base amount of ₹10,000 and GST is 18%, the GST amount is ₹1,800 and the final amount is ₹11,800.

GST Formula

GST Amount = (Base Amount × GST Rate) / 100

Final Amount = Base Amount + GST Amount

Reverse GST Formula: GST Amount = Inclusive Price − (Inclusive Price × 100 / (100 + GST%))

CGST vs SGST vs IGST

CGST and SGST are used for intrastate transactions, where the seller and buyer are in the same state. The GST amount is split equally between Central GST and State GST. IGST is used for interstate transactions, where the full GST amount is shown as Integrated GST.

GST Rates in India

Common calculator slabs historically include 0%, 5%, 12%, 18%, and 28%, with special categories such as 3%. GST Council rate rationalisation material published in September 2025 also refers to a simplified 5% and 18% structure with a special 40% de-merit rate for select goods and services. The correct GST slab depends on the product or service category, so businesses should verify the applicable rate before issuing invoices.

GST Calculation Examples

For an exclusive GST invoice of ₹50,000 at 18%, GST is ₹9,000 and the final invoice value is ₹59,000. For an inclusive price of ₹59,000 at 18%, the taxable value is ₹50,000 and the GST component is ₹9,000.

GST for Startups

Startups use GST calculations while pricing SaaS subscriptions, consulting services, ecommerce products, and agency deliverables. Clean GST calculations help founders quote accurately and avoid confusion between taxable value and customer payable amount.

GST for Freelancers

Freelancers often need to add GST to retainers, project fees, and recurring invoices. This calculator helps freelancers show base fee, GST amount, CGST, SGST, IGST, and final payable amount clearly.

GST for Ecommerce Sellers

Ecommerce sellers use GST to plan product pricing, discounts, platform fees, and invoice totals. The GST on discount tool is useful when a seller wants to apply GST after a discount rather than on the original MRP.

GST for Agencies

Agencies can use GST calculations for retainers, website projects, ad management fees, performance marketing invoices, and design services. The profit margin calculator helps estimate selling price and invoice value from internal cost.

Benefits of Using GST Calculator

A GST calculator reduces manual errors, speeds up invoice planning, clarifies inclusive and exclusive pricing, and gives business owners a quick way to compare GST rates before sharing quotes with customers.