How do I calculate GST?

To calculate the GST amount, multiply the base amount by the GST rate and divide by 100: GST Amount = (Original Cost × GST Rate) / 100. Total price = Original Cost + GST Amount.

What is the difference between CGST and SGST?

When a transaction happens within the same state (intra-state), GST is split equally between CGST (Central GST) and SGST (State GST). For transactions between two different states (inter-state), the full GST amount is charged as IGST.

What is a reverse GST calculator?

A reverse GST calculator is used when you already have a GST-inclusive total amount and need to work out the original taxable value and the GST amount separately.

What are the current GST rate slabs?

Under GST 2.0, effective from 22 September 2025, India moved to a simplified structure with three main slabs: 0% (nil), 5%, and 18%, plus a special 40% rate for select luxury and sin goods. The earlier 12% and 28% slabs were removed, with most items shifted into 5% or 18%.

What is GST 2.0 and when did it take effect?

GST 2.0 refers to the major reform approved at the 56th GST Council meeting, effective from 22 September 2025. It simplified the tax structure from five slabs (0%, 5%, 12%, 18%, 28%) down to mainly three — 0%, 5%, and 18% — with a 40% rate applied to luxury and sin goods.

Is this GST calculator free to use?

Yes, this GST calculator is completely free to use and does not require any login or sign-up.

India's Trusted GST Calculator

Calculate GSTin Seconds

Use the free GST calculator below to work out the GST amount on your product or service in seconds — add GST to a base price or reverse-calculate it from a GST-inclusive amount, with a full CGST/SGST or IGST breakup.

Fast & Accurate
GST 2.0 Rates
100% Free · No Signup

Hanu holding a GST invoice with CGST, SGST, IGST and reverse GST

Your Result

₹0.00

Base Amount₹0.00

GST Amount (18%)₹0.00

Tax Breakup

CGST (9%)₹0.00

SGST (9%)₹0.00

Results will be displayed here after calculation.

Understanding GST

What is GST?

A GST calculator is a free online tool that computes Goods and Services Tax (GST) instantly and without errors. Whether you're a business owner, freelancer, retailer, or just want to check an invoice — this online GST calculator gives you the taxable amount, CGST, SGST or IGST, and the total invoice value in seconds. Manual calculations leave room for mistakes, but with this calculator you get a 100% accurate result every time.

CGST

Central GST is levied by the Central Government on intra-state transactions.

SGST

State GST is levied by the State Government on intra-state transactions.

IGST

Integrated GST is levied by the Central Government on inter-state transactions.

GST Formula

How to Calculate GST

Two simple formulas cover almost every invoice. Same-state bills split GST equally into CGST and SGST. Different-state bills charge the full amount as IGST.

Add GST

Tax-exclusive price

GST Amount(Original Amount × GST Rate) / 100
Total PriceOriginal Amount + GST Amount

Example: ₹10,000 at 18% → GST ₹1,800 · Total ₹11,800

Reverse GST

Tax-inclusive price

Taxable ValueInclusive Amount / (1 + GST Rate / 100)
GST AmountInclusive Amount − Taxable Value

Example: ₹11,800 incl. 18% → Taxable ₹10,000 · GST ₹1,800

Place of supply

CGST + SGST or IGST

Same StateCGST + SGST

Intra-state supply. GST splits equally — 9% + 9% on an 18% invoice.

Different StateIGST

Inter-state supply. The full GST is charged as a single IGST line.

How to use

How to Use the Calculator

01Choose a mode
Pick Add GST for a tax-exclusive price, or Reverse GST when the amount already includes tax.
02Enter the amount
Type the base price in Add GST, or the GST-inclusive total in Reverse GST.
03Select the GST rate
Use 0%, 5%, 18% or 40%, depending on the product or service.
04Same state or different state
Same state splits GST into CGST + SGST. Different state charges the full amount as IGST.
05Read the result
You get the taxable amount, CGST/SGST or IGST, and the invoice total.

This tool is for estimation purposes only. For official GST filing, please confirm figures with your CA or the official GST portal (gst.gov.in).

GST Rate Slabs (2026) — GST 2.0

Current GST Rate Slabs

Following the 56th GST Council meeting, India moved to a simplified GST 2.0 structure from 22 September 2025. The old five-slab system (0%, 5%, 12%, 18%, 28%) was replaced with 0%, 5% and 18%, plus a special 40% rate for luxury and sin goods.

0%Essential Goods & Services

5%Daily Essentials

18%Standard Items

40%Luxury & Sin Goods

A few niche rates still exist, such as 3% on gold/jewellery and 0.25% on rough precious stones. Confirm the HSN/SAC rate before invoicing.

Frequently Asked Questions

Related Calculators

Plan tax, salary and investments alongside GST

Income Tax CalculatorOld vs new regime tax Salary CalculatorCTC to in-hand salary SIP CalculatorPlan your mutual fund SIP FD CalculatorCheck fixed deposit returns Home Loan CalculatorCalculate your EMI