How do I calculate GST on a price?

GST amount = taxable value × GST rate ÷ 100. Total invoice value = taxable value + GST. Example: ₹1,000 at 18% GST is ₹180 tax and ₹1,180 total. On this page, enter the amount, pick the rate, and the GST calculator shows the breakdown instantly.

What are the new GST slabs from 22 September 2025?

From 22 September 2025, GST in India is largely 5% (merit rate), 18% (standard rate), and 40% for a small set of luxury and sin goods. Nil (0%) still applies to specified essentials. The older 12% and 28% slabs were largely removed. Some tobacco products stay on earlier GST plus compensation cess until notified otherwise. Always confirm the rate for your HSN or SAC.

What is the difference between CGST, SGST, and IGST?

Intra-state supplies (same state) split GST equally into CGST and SGST. Inter-state supplies and imports use IGST at the full rate. The tax total is the same; only the split changes. Example: 18% intra-state is 9% CGST + 9% SGST. Inter-state is 18% IGST.

How do I reverse GST from an inclusive amount?

Taxable value = inclusive amount ÷ (1 + GST rate). GST = inclusive amount − taxable value. Example: ₹1,180 including 18% GST has a taxable value of ₹1,000 and GST of ₹180. Select Amount Includes GST on this calculator to reverse GST automatically.

Is this GST calculator free? Do I need to sign up?

Yes. TiBook’s GST calculator is free, runs in the browser, and does not require an account, demo, or download. Use it as often as you need. To turn the result into a GST invoice, use the free invoice generator.

Can I still calculate 12% or 28% GST?

Yes. Type any custom rate, including 12% or 28%, for older invoices, credit notes, or goods that still use a notified rate. The calculator is not limited to the new 5%, 18%, and 40% slabs.

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GST Calculator with New GST Slabs

Calculate GST with the 5%, 18%, and 40% slabs in force from 22 September 2025. Split CGST + SGST or IGST. Add GST or reverse it from a tax-inclusive amount. Free, no signup.

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Calculate GST

Enter the amount, pick a GST slab, then choose intra-state or inter-state and whether GST is already included.

Amount (₹)

GST Rate (%)

New slabs from 22 Sep 2025: 5%, 18%, and 40%. Use 12% or 28% for older invoices, or type any custom rate.

Transaction Type

Amount Type

Calculation Results

Enter an amount to calculate GST

Free online GST calculator for Indian businesses

GST mistakes show up on invoices, GSTR-1, and cash. This GST calculator is for shop owners, traders, accountants, and anyone who needs a correct tax amount before they bill.

Enter a rupee amount, pick the GST rate, and see taxable value, GST, and the invoice total. Intra-state supplies split into CGST and SGST. Inter-state supplies use IGST. You can add GST on a net price or reverse GST from a tax-inclusive price.

Why this GST calculator is different

Most free GST calculators only multiply a price by a rate. That is not how Indian invoices work. You need the right slab, the right split, and a way to work backwards from a GST-inclusive amount.

✓New GST slabs, not last year’s rates. Presets include 5%, 18%, and 40% from 22 September 2025. 12% and 28% stay available for older invoices.
✓CGST + SGST or IGST, not a single GST line. Same-state sales split the tax. Other-state sales and imports use IGST. The total is the same; the split is what your invoice and returns need.
✓Add GST or reverse GST. Exclusive mode puts tax on a net price. Inclusive mode takes GST out of an MRP or quoted total so you can see the taxable value.
✓No signup, demo, or download. The math runs in the browser. When you need a GST invoice from the same numbers, open the free invoice generator.

New GST slabs from 22 September 2025

The 56th GST Council meeting simplified the old 5%, 12%, 18%, and 28% structure. Confirm the rate for your HSN or SAC before you invoice.

Current GST rates

0% (nil): Specified essentials — for example UHT milk, paneer, and Indian breads such as roti and paratha, as notified.
5% (merit rate): Many household and common-use goods moved here from 12% or 18% — soaps, toothpaste, hair oil, bicycles, tableware, and similar items.
18% (standard rate): Most goods and services, including a large share of items that were previously 12% or 28%.
40% (de-merit rate): A small set of luxury and sin goods, such as specified high-end vehicles and aerated drinks, in place of 28% plus cess on many of those lines.

What changed

12% and 28% were largely removed. Most 12% items moved to 5% or 18%. Most 28% items moved to 18% or 40%. Individual health and life insurance were made nil-rated. Pan masala, gutkha, cigarettes, chewing tobacco, and bidi stay on earlier GST and compensation cess until the Council notifies otherwise.

This page is a calculator, not tax advice. Use the GST rate notified for your goods or services.

How to use this GST calculator

1. Enter the amount. Use the net price if GST is not included. Use the billed or MRP amount if GST is already in the figure.
2. Select the GST rate. Tap 5%, 18%, or 40% for the new slabs, or type a custom rate.
3. Choose intra-state or inter-state. Same state: CGST + SGST. Different states: IGST.
4. Choose exclusive or inclusive. Exclusive adds GST. Inclusive reverse-calculates GST from the total.

The result updates as you type: base amount, tax split, total GST, and invoice total, with the formula shown under the numbers.

GST formula

GST is charged on the taxable value, not on a guess. These are the two formulas this tool uses.

Add GST (amount excludes tax)

GST amount = Amount × GST rate ÷ 100

Invoice total = Amount + GST amount

Example: ₹1,000 at 18% → GST ₹180, total ₹1,180. Intra-state that is CGST ₹90 + SGST ₹90. Inter-state that is IGST ₹180.

Reverse GST (amount includes tax)

Taxable value = Inclusive amount ÷ (1 + GST rate)

GST amount = Inclusive amount − taxable value

Example: ₹1,180 including 18% → taxable value ₹1,000, GST ₹180.

CGST, SGST, and IGST

CGST: Central GST on intra-state supplies. Half of the GST rate.
SGST / UTGST: State or Union Territory GST on intra-state supplies. The other half.
IGST: Integrated GST on inter-state supplies and imports, at the full rate.

Place of supply decides the split, not where you prefer to book the tax. A Gujarat seller billing a Gujarat buyer uses CGST + SGST. The same seller billing a Maharashtra buyer uses IGST. This calculator lets you switch that without redoing the arithmetic.

GST registration, e-invoicing, and returns

Registration: GST registration is generally required when aggregate turnover exceeds ₹20 lakh (₹10 lakh in specified special-category states). Some supplies need registration regardless of turnover.

E-invoicing: Businesses above the notified turnover (currently ₹5 crore) must report B2B invoices to the Invoice Registration Portal and print the IRN and QR code.

Returns: GSTR-1 reports outward supplies. GSTR-3B is the summary return with tax payment. GSTR-9 is the annual return. Late fees and interest apply if you file or pay late.

A calculator does not file your return. It keeps the tax on the invoice aligned with what you will later report. For GST-ready invoices, use TiBook’s invoice generator.

Why the GST amount has to be right

✓The invoice is the source document. Wrong GST on the bill flows into GSTR-1, the buyer’s ITC, and any e-invoice you generate.
✓Input tax credit. Buyers claim ITC on the tax you charged. An overstated or understated GST line creates a mismatch.
✓Cash. Under-collecting GST means you pay the difference. Over-collecting without a matching rate is a compliance problem, not extra profit.

GST calculator FAQs

Put the GST amount on a real invoice

Calculate tax here, then create a GST invoice with line items, tax, and PDF download. No signup on the generator either.

Create a GST invoice Save invoices in TiBook

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