India GST Calculator
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
| Supply type | Tax components shown | How tax is applied (typical) | When commonly used |
|---|---|---|---|
| Intra-state | CGST + SGST | GST split equally: CGST = G/2, SGST = G/2 | Supplier and place of supply in the same state/UT |
| Inter-state | IGST | IGST equals total GST: IGST = G | Supplier and place of supply in different states/UTs |
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.