How it works
Select whether the amount includes GST. For the intra-state scenario, the total tax is split equally into CGST and SGST. For the inter-state scenario, it is shown as IGST. Use the rate applicable to your goods or services.
Inputs and units
| Input | Example value | What to enter |
|---|---|---|
| Amount | ₹10,000.00 | Required unit: ₹. Use a non-negative value. |
| Applicable GST rate | 18 % | Enter the percentage as a number: for 15%, enter 15. Use a non-negative value. Allowed range: 0–100. |
| Amount entered | Exclusive of GST | Check the selected option before calculating. |
| Supply type | Intra-state — CGST + SGST | Check the selected option before calculating. |
Worked example
Show example inputs and results
This example is generated by the same calculation engine using the starting values in the form. Your own inputs produce your own result.
- Amount
- ₹10,000.00
- Applicable GST rate
- 18 %
- Amount entered
- Exclusive of GST
- Supply type
- Intra-state — CGST + SGST
Complete example results
- Amount including GST
- ₹11,800.00
- Amount before tax
- ₹10,000.00
- Tax amount
- ₹1,800.00
- CGST
- ₹900.00
- SGST
- ₹900.00
Reading the result
Match the rate period to the payment period. Fees and taxes absent from the inputs are not added automatically; compare totals with the same cost coverage.
Why subtracting 18% does not remove 18% GST
For a GST-inclusive ₹1,180 at an assumed 18% rate, divide by 1.18 to get ₹1,000 before tax. Subtracting 18% of ₹1,180 instead gives ₹967.60, which is not the taxable base.
Check the input mode before comparing invoices
Exclusive mode adds tax to your input; inclusive mode separates tax already inside it. Choose the applicable supply scenario yourself. The calculator does not establish a tax rate, place of supply or entitlement to input credit.
Compare different scenarios
Inputs held constant: Amount: 1,180 ₹ · Amount entered: Inclusive of GST · Supply type: Intra-state — CGST + SGST.
| Applicable GST rate | Amount before tax | Tax amount |
|---|---|---|
| 5 % | ₹1,123.81 | ₹56.19 |
| 12 % | ₹1,053.57 | ₹126.43 |
| 18 % | ₹1,000.00 | ₹180.00 |
Questions and answers
Can I use the example values for my own calculation?
The example values illustrate the calculation. Replace every input with your own information, especially dates, rates and the selected operation.
Does the tool determine the correct GST rate?
No. The displayed rate is an example. Classification, place of supply, exemptions and current notifications determine the actual treatment. The tool only applies your inputs.
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method sources: cbic-gst.gov.in
Data version: 2026-10-08 · Methods & accuracy