💰 Finance & Money

🧾 GST Calculator

Goods and Services Tax (GST) touches almost every invoice, bill and purchase in India, but working out the exact tax component by hand is easy to get wrong — especially when you need to split it into CGST and SGST for an intra-state sale, or show IGST for an inter-state one. This GST calculator does the arithmetic instantly, whether you're adding GST to a base price to arrive at the final billing amount, or removing GST from a GST-inclusive price to find the original value.

It supports the four common slabs used in India — 5%, 12%, 18% and 28% — as well as any custom rate, so it works for restaurant bills, freelance invoices, e-commerce pricing or simple back-of-envelope checks before you file a return.

Amount (₹)

Add GST (base price entered) Remove GST (final price entered)

GST rate

Enter an amount to see the GST breakdown.

How to use the GST Calculator

Enter the amount you're starting with — either the base price (before tax) or the total price (after tax).
Choose whether you want to Add GST to that amount or Remove GST from it.
Pick a GST rate — 5%, 12%, 18%, 28% or a custom percentage.
Read off the base amount, GST amount, CGST/SGST split and final total instantly.

How GST is calculated

When adding GST to a base amount: GST amount = Base × (rate / 100), and Final amount = Base + GST amount.

When removing GST from a GST-inclusive amount: Base amount = Total ÷ (1 + rate / 100), and GST amount = Total − Base amount.

For sales within the same state, GST is usually split equally into CGST (Central GST) and SGST (State GST) — each is half the total GST amount. For sales between different states, the full amount is charged as IGST (Integrated GST) instead of splitting it.

Frequently asked questions

What's the difference between adding and removing GST?

Adding GST starts from a base (pre-tax) price and calculates the tax on top of it. Removing GST starts from a final, tax-inclusive price (e.g. an MRP or a bill total) and works backwards to find the original base price and the tax hidden inside it.

How is CGST and SGST split calculated?

For an intra-state (within the same state) sale, the total GST amount is split equally: CGST = GST amount ÷ 2, and SGST = GST amount ÷ 2. Together they add up to the total GST charged.

When is IGST used instead of CGST/SGST?

IGST applies to inter-state transactions — when the buyer and seller are in different states — and to imports. Instead of splitting the tax, the full GST amount is charged as a single IGST line.

Is this calculator accurate for GST return filing?

This tool gives a fast, accurate arithmetic check for a single amount and is useful for invoices, quotes and sanity-checking bills. For actual GST return filing, always use the GST portal or your accounting software, since filing also involves input tax credit and other adjustments this simple calculator doesn't track.

📖 Related reading: How to Calculate GST in India: A Complete Guide