GST Calculator India – Add or Remove GST (CGST, SGST, IGST)

Quickly calculate Goods and Services Tax (GST) in India at 5%, 12%, 18%, 28% (and other slab rates). Add GST to a base price or remove GST from an inclusive price, and see the split into CGST, SGST, or IGST.

GST Calculator (India)

For “Add GST”, enter the base (taxable) value. For “Remove GST”, enter the GST-inclusive amount.

Custom: %
Mode
Add GST to base price
Base amount (before GST)
₹0.00
Total GST amount
₹0.00
Effective GST rate: 0.00%
CGST
₹0.00
SGST
₹0.00
Total invoice amount
₹0.00

How to calculate GST in India

Goods and Services Tax (GST) in India is a destination-based indirect tax levied on the supply of goods and services. For most practical purposes, you either:

  • Add GST to a base (taxable) value to get the invoice value, or
  • Remove GST from a GST-inclusive price to find the base value and tax component.

1. Formula to add GST (exclusive → inclusive)

Given: Base value = \( V \), GST rate = \( r\% \)

GST amount:

\[ \text{GST amount} = V \times \frac{r}{100} \]

Invoice value (including GST):

\[ \text{Invoice value} = V + \text{GST amount} \]

Example: Base value ₹1,000 at 18% GST

  • GST amount = 1,000 × 18 ÷ 100 = ₹180
  • Invoice value = 1,000 + 180 = ₹1,180

2. Formula to remove GST (inclusive → base)

Given: GST-inclusive value = \( G \), GST rate = \( r\% \)

Base value (before GST):

\[ \text{Base value} = \frac{G}{1 + \frac{r}{100}} \]

GST amount:

\[ \text{GST amount} = G - \text{Base value} \]

Example: Inclusive price ₹1,180 at 18% GST

  • Base value = 1,180 ÷ 1.18 ≈ ₹1,000
  • GST amount = 1,180 − 1,000 = ₹180

3. CGST, SGST and IGST split

The total GST rate is shared between the Centre and the States depending on whether the supply is intra-state or inter-state:

  • Intra-state supply (same State/UT): GST is split into CGST and SGST/UTGST, usually 50% each of the total rate.
    Example: 18% GST → 9% CGST + 9% SGST.
  • Inter-state supply (different States/UTs or exports): GST is charged as IGST at the full rate.
    Example: 18% GST → 18% IGST.

The calculator automatically splits the tax into CGST + SGST or IGST based on the tax type you select.

GST slab rates in India

The GST Council notifies GST rates for goods and services. Broadly, the main slabs are:

  • 0% – Essential items, many food items, exports (zero-rated), etc.
  • 5% – Essential goods and services (e.g. certain food items, transport).
  • 12% – Standard goods/services in the mid-range.
  • 18% – Most goods and services fall under this slab.
  • 28% – Luxury goods and “sin” goods (e.g. certain cars, tobacco products), often with additional cesses.

There are also special rates such as 0.1% and 3% for specific categories (e.g. precious metals). Always refer to the latest notifications from the CBIC for current rates.

Worked examples with this GST calculator

Example A – Add 18% GST (intra-state supply)

  1. Select Add GST mode.
  2. Enter ₹10,000 as the amount.
  3. Choose 18% GST rate.
  4. Select Intra-state (CGST + SGST).

The calculator will show:

  • Base amount: ₹10,000
  • GST amount: ₹1,800
  • CGST: ₹900, SGST: ₹900
  • Total invoice amount: ₹11,800

Example B – Remove 12% GST from an inclusive price

  1. Select Remove GST mode.
  2. Enter ₹5,600 as the amount (inclusive of GST).
  3. Choose 12% GST rate.

The calculator will compute:

  • Base amount ≈ ₹5,000
  • GST amount ≈ ₹600
  • If intra-state: CGST ≈ ₹300, SGST ≈ ₹300

Frequently asked questions about GST calculation in India

Is GST calculated on MRP or transaction value?

Legally, GST is levied on the transaction value (price actually paid or payable), which may be equal to or lower than the printed MRP. Discounts shown on the invoice before tax reduce the taxable value; post-supply discounts may be adjusted subject to conditions.

How do I calculate GST for a mixed supply with different rates?

If your invoice contains items with different GST rates (e.g. 5% and 18%), calculate GST item-wise:

  • Compute GST for each line item using its applicable rate.
  • Sum up the base values and tax amounts to get the invoice totals.

You can run the calculator multiple times for each rate, or use it as a quick check for individual lines.

Does this calculator handle cess (e.g. compensation cess)?

This tool focuses on GST rate only (CGST, SGST, IGST). If a particular good attracts an additional compensation cess (e.g. certain luxury or sin goods), you should calculate the cess separately as per the notified rate and add it on top of the GST amount.

Is GST the same across all Indian states?

The GST rate structure is uniform across India, but the sharing of tax between Centre and States differs (CGST + SGST vs IGST). Some items may be exempt or taxed differently based on notifications, so always check the latest CBIC and State GST updates.

Disclaimer

This GST calculator is for educational and quick-estimation purposes only. It does not replace professional tax advice or official GST software. For filing returns and compliance, always rely on your accountant, tax consultant, or the official GST portal and notifications.