GST Calculator
Add GST to a pre-tax price or extract the GST portion from a GST-inclusive amount.
Enter your details
Choose the GST rate and treatment that apply to the transaction. This tool does not determine tax classification or filing obligations.
Your result
Enter your details to calculate.
Worked example
Sample inputs
- Currency
- Indian rupee (INR)
- Amount
- 1000
- GST rate (%)
- 18%
- Amount entered is
- Before GST (exclusive)
Total including GST: ₹1,180.00
- Pre-tax amount: ₹1,000.00
- GST amount: ₹180.00
- GST rate: 18%
How this gst calculator works
For an exclusive price, GST is price × rate ÷ 100. For an inclusive total, the tax portion is total × rate ÷ (100 + rate).
Choose the GST rate and treatment that apply to the transaction. This tool does not determine tax classification or filing obligations.
Frequently asked questions
How do I calculate GST on a pre-tax price?
Select “Before GST (exclusive)”. The calculator adds the selected percentage to the entered base amount.
How do I find GST inside an inclusive price?
Select “Including GST (inclusive)”. The tax portion is separated from the total using rate ÷ (100 + rate).