GST Calculator

Calculate GST both ways

Add GST to a base price to find the invoice total, or remove GST from a tax-inclusive amount to find the taxable value. For intra-state supply, GST is divided equally between Central GST (CGST) and State GST (SGST), and the calculator shows both halves automatically.

Outputs

• Net (taxable) amount
• Total GST and the CGST / SGST split
• Final amount including GST

Key features at a glance

• Add or remove GST at any rate
• Automatic equal CGST and SGST split for intra-state supply
• Preset buttons for the 3%, 5%, 12%, 18%, and 28% slabs
• Shows net (taxable) amount, total GST, and final amount
• Works in both directions — inclusive and exclusive
• Runs entirely in your browser, even offline

How GST is added and removed

GST, or Goods and Services Tax, is a value-added tax applied to most goods and services. To add GST, you multiply the base (taxable) price by one plus the GST rate, so a 1,000 supply at 18% becomes 1,180, of which 180 is GST. This gives the invoice total a customer pays.

To remove GST from a tax-inclusive amount, you divide by one plus the rate rather than subtracting the percentage. A 1,180 GST-inclusive price at 18% divides back to 1,000 taxable value with 180 of GST. This reverse calculation is essential for sellers working out the taxable value from a final price and for buyers separating the GST component on a receipt.

Understanding the CGST and SGST split

Under India's GST system, tax on a transaction is divided depending on whether the supply is within a state or between states. For intra-state supply, the GST is split equally into Central GST (CGST) and State GST (SGST), each taking half the total. So 18% GST becomes 9% CGST plus 9% SGST, and the calculator shows both halves automatically.

For inter-state supply, a single Integrated GST (IGST) applies instead, equal to the full rate, and is not split. Knowing which applies matters for correct invoicing and filing: charging CGST and SGST on an inter-state sale, or IGST on an intra-state one, creates compliance problems. This tool focuses on the common intra-state split so your invoices show the right components.

The GST rate slabs

GST is organized into rate slabs that group goods and services by category. The main slabs are 5%, 12%, 18%, and 28%, with a special 3% rate for items like gold and a 0% rate for many essentials. Everyday goods tend to sit in the lower slabs, while luxury and so-called sin goods attract the highest 28% rate.

The preset buttons cover these standard slabs so you can apply the right rate with a single tap rather than typing it each time. Because the correct slab depends on the specific product or service, it is worth confirming the applicable rate for what you are invoicing, but the presets make the common cases fast and reduce the chance of a typo in the rate.

Tips for using the GST calculator

• Use the presets to apply the correct slab quickly and avoid typos
• To remove GST, divide by (1 + rate), never subtract the percentage
• Apply the CGST/SGST split for intra-state supply only
• Use IGST at the full rate for inter-state transactions
• Keep the net, GST, and total figures for compliant invoicing

Why choose our GST calculator?

Our calculator is completely free with no signup, no limits, and no subscription. It runs entirely in your browser, so results are instant, it works offline, and your figures are never sent to a server.

It is one of more than 200 free tools on ToopTools, and you can pin it to your My Workspace, a personalized workspace where you keep the tools you use most in a single dashboard. Beside the sales tax and other finance tools, it makes GST invoicing and reconciliation quick and accurate.

Common use cases

Business owners, freelancers, and accountants use the GST calculator to prepare invoices with the correct tax and CGST/SGST split, and to back out the taxable value from GST-inclusive prices for their records. The presets make applying the right slab fast during day-to-day billing.

Buyers use it to understand how much GST they are paying on a purchase, and small sellers use it to set GST-inclusive prices that still yield the margin they need. Because it handles both directions, it fits both the seller raising an invoice and the bookkeeper reconciling receipts.

Is the GST calculator free?

Yes. It is completely free with no account, no sign-up, and no usage limits. Calculate as much GST as you like at no cost.

How do I remove GST from a price?

Divide the GST-inclusive amount by one plus the GST rate as a decimal. At 18%, divide by 1.18 to find the taxable value, and the difference is the GST.

What is the CGST and SGST split?

For intra-state supply, GST is divided equally into Central GST and State GST. An 18% rate becomes 9% CGST plus 9% SGST. The calculator shows both halves automatically.

When does IGST apply instead?

Integrated GST applies to inter-state supplies and to imports. It equals the full GST rate and is not split into CGST and SGST. The CGST/SGST split applies only within a single state.

What are the standard GST slabs?

The main slabs are 5%, 12%, 18%, and 28%, with a 3% rate for items like gold and 0% for many essentials. The correct slab depends on the specific good or service being supplied.

Can I set a GST-inclusive selling price?

Yes. Decide the final price you want to charge, then use the remove-GST mode to see the taxable value and GST inside it. This lets you set a round, GST-inclusive price while still recording the correct net amount and tax for your books.

Are my figures kept private?

Yes. Everything is computed in your browser and nothing is uploaded, so your amounts stay private and the tool works without an internet connection.

How do I add GST to a price?

Enter the base price and the GST rate, and the calculator instantly shows the GST amount and the GST-inclusive total, split into CGST and SGST where applicable. Switch to the reverse mode to extract GST from a tax-inclusive price.

Does the GST calculator work offline?

Yes. The calculation runs entirely in your browser, so once the page has loaded the tool works without an internet connection, and your figures are never uploaded — they stay private on your own device.