OptiDrop

GST Calculator Online India — Add & Remove GST Free

Calculate GST amount and total price for any rate (5%, 12%, 18%, 28%). Also supports reverse GST to find the original price from a GST-inclusive amount. 100% free, no sign-up.

GST Calculator — About This Tool

The OptiDrop GST Calculator is a free online tool that lets you add or remove Goods and Services Tax from any amount at all four standard Indian GST rates — 5%, 12%, 18%, and 28%. Whether you are a small business owner preparing invoices, a freelancer calculating project costs, or a consumer checking the tax breakdown on a bill, this calculator gives you instant and accurate results. Everything runs in your browser, so your financial data stays completely private.

How to Use the GST Calculator

  1. Enter the base amount (to add GST) or the final price (to remove GST) in the input field.
  2. Select the applicable GST rate from the dropdown — 5%, 12%, 18%, or 28%.
  3. Choose whether you want to add GST to a base price or extract GST from an inclusive price using the tab switcher.
  4. Click the calculate button and instantly see the GST amount, original price, and total price displayed in a clear summary.

Frequently Asked Questions

What are the different GST rates in India and when do they apply?

India uses a four-tier GST structure. The 5% rate applies to essential goods like packaged food items and economy-class air tickets. The 12% rate covers processed foods, business-class air tickets, and certain industrial inputs. The 18% rate is the most common and applies to most goods and services including electronics, restaurants, and professional services. The 28% rate is reserved for luxury and demerit items such as automobiles, tobacco products, and aerated beverages. Some goods and services are also exempt or taxed at 0%.

What is the difference between adding GST and removing GST?

Adding GST means calculating the tax on top of a base price to arrive at the final selling price. For example, if your product costs Rs. 1,000 and you add 18% GST, the total becomes Rs. 1,180. Removing GST (also called reverse GST) works the opposite way — you start with a GST-inclusive price and back-calculate the original amount. For Rs. 1,180 at 18%, the original price is Rs. 1,000 and the GST component is Rs. 180. This is useful when you receive a bill and want to know the pre-tax cost.

What is IGST and how does it differ from CGST and SGST?

IGST (Integrated GST) is charged on interstate transactions where the supplier and buyer are in different states. It is collected by the central government and then distributed between the centre and the destination state. CGST (Central GST) and SGST (State GST) are charged on intrastate transactions, where both parties are in the same state. In that case, the GST rate is split equally — for example, 18% GST becomes 9% CGST plus 9% SGST. The total tax burden remains the same regardless of whether IGST or CGST+SGST applies.

Can businesses use this GST calculator for filing returns?

Yes, this calculator is helpful for quickly verifying GST amounts on invoices before filing returns. However, it is a tool for calculation only — it does not file returns directly or connect to the GST portal. For actual return filing, you will need to use the official GSTN portal or authorized GST Suvidha Providers. The calculator is ideal for double-checking figures, preparing quotations, and understanding the tax breakdown on purchases. All calculations happen locally in your browser, so your financial data is never sent to any server.

Free GST Calculator Online — Add & Remove GST Instantly

OptiDrop's GST Calculator is a free online tool designed for businesses, freelancers, and consumers in India. It helps you quickly calculate the GST amount on any product or service and also reverse-calculate the original price from a GST-inclusive amount. Whether you are filing invoices, checking bills, or pricing products, this tool handles it all instantly.

Add GST to Any Price

Enter the original amount and select the applicable GST rate (5%, 12%, 18%, or 28%). The calculator instantly shows you the GST amount and the total price including GST. This is useful for sellers who need to add GST to their base price before issuing invoices.

Remove GST from a Price (Reverse GST)

If you have a GST-inclusive price and need to find out how much GST was charged, switch to the "Remove GST" tab. Enter the final price and the GST rate, and the tool will show you the original price before GST and the GST portion. This is helpful for consumers who want to know the pre-tax cost of a product or for businesses extracting input tax credit amounts.

Frequently Asked Questions

GST stands for Goods and Services Tax. It is a comprehensive indirect tax levied on the supply of goods and services in India. It replaced multiple indirect taxes like VAT, service tax, and excise duty, creating a unified national tax system.
To add GST to a price, multiply the original amount by the GST rate percentage and divide by 100. For example, for Rs. 1000 at 18% GST: GST amount = 1000 x 18/100 = Rs. 180. Total price = 1000 + 180 = Rs. 1180.
India has four main GST rates: 5% (essential goods like packaged food), 12% (processed food, computers), 18% (most goods and services, electronics, restaurants), and 28% (luxury items, cars, tobacco, aerated drinks). Some items are also exempt or at 0% GST.
To remove GST from a price, divide the total price by (1 + GST rate/100). For example, if the total is Rs. 1180 at 18% GST: Original price = 1180 / 1.18 = Rs. 1000. GST amount = 1180 - 1000 = Rs. 180.

Last updated: June 2026