India GST Calculator

Introduction: Understanding India’s Goods and Services Tax (GST)

India introduced the Goods and Services Tax (GST) in 2017 to replace a patchwork of indirect taxes (such as excise duty, service tax, VAT, and octroi) with a unified, destination-based system. “Destination-based” means the tax revenue is attributed to the place where goods or services are consumed, not where they are produced.

This calculator helps you estimate GST on a tax-exclusive base price and then shows how the tax is applied depending on the nature of supply:

• Intra-state supply: GST is split into CGST (Central GST) and SGST (State GST), typically in equal halves.
• Inter-state supply: GST is charged as IGST (Integrated GST) as a single amount.

What this calculator computes

You provide (1) the base price (taxable value), (2) a GST rate slab, and (3) whether the supply is intra-state or inter-state. The calculator then outputs:

• Total GST amount
• CGST and SGST (if intra-state) or IGST (if inter-state)
• Total price including GST

GST formulas

Let:

• B = base price (tax-exclusive taxable value)
• r = GST rate (in percent, e.g., 18)
• G = total GST amount

The core computation is:

G = B × (r / 100)

Intra-state (CGST + SGST)

• CGST = G / 2
• SGST = G / 2
• Total including GST = B + G

Inter-state (IGST)

• IGST = G
• Total including GST = B + G

Worked example

Example: Base price ₹10,000, GST rate 18%.

• Total GST: 10,000 × 18/100 = ₹1,800
• Intra-state: CGST ₹900 and SGST ₹900; total including GST = ₹11,800
• Inter-state: IGST ₹1,800; total including GST = ₹11,800

Interpreting the results

• Total GST shows the tax amount on top of your base price (as entered).
• CGST/SGST split appears only for intra-state supplies. The split is shown equally for typical cases where state GST is applied at the same rate as central GST.
• IGST appears only for inter-state supplies as a single consolidated tax.
• Total price (incl. GST) is the final value after adding GST to the base price.

Quick comparison table

Assumptions, limitations, and what’s not included

• Tax-exclusive input: The “Base Price” is treated as the taxable value before GST. If you have a GST-inclusive amount, you must first convert it to a base value (this page does not invert inclusive pricing).
• Cess not included: Some goods attract an additional compensation cess. This calculator does not add cess.
• Exempt/zero-rated cases not modeled: Exempt supplies, nil-rated items, and zero-rated exports can follow different treatment. This calculator assumes a taxable supply at the chosen slab.
• Rate selection is manual: You must choose the correct slab (e.g., 5%, 12%, 18%, 28%) based on the product/service classification.
• Rounding: Results may be rounded for display (for example, to two decimal places). Invoice-level rounding can vary by business practice and accounting system.
• Discounts/freight/other charges: If your invoice includes discounts, shipping, packing, or other charges that affect taxable value, enter the correct taxable base after applying the relevant rules.
• Reverse charge and ITC not covered: This tool is for computing output GST amounts only. It does not determine reverse charge applicability, input tax credit eligibility, or return-filing obligations.
• Informational only: GST law and interpretations can change; verify with official notifications or your tax professional for compliance decisions.

Rates note

This calculator includes the most common GST slabs (5%, 12%, 18%, and 28%). Special rates (for example, certain precious metals) and category-specific rules are not included here.

How to use this calculator

1. Enter Base Price using the unit or time period shown by the field.
2. Enter GST Rate 5% 12% 18% 28% using the unit or time period shown by the field.
3. Enter Supply Type Intra-state (CGST + SGST) Inter-state (IGST) using the unit or time period shown by the field.
4. Run the calculation and compare the output with a second scenario before acting on it.