GST Calculator
Add GST to a base price to find the total, or start from a GST-inclusive price and work backward to find the base amount and the tax component hidden inside it.
GST calculator
Add GST to a base price, or work backward from a GST-inclusive price to find the base amount and tax component.
Pure arithmetic, not tax advice. GST rates and rules change and vary by good/service — always confirm the applicable rate for your actual transaction.
The two directions
Adding GST (exclusive → inclusive): GST amount = Base amount × (rate ÷ 100); Total = Base amount + GST amount.
Removing GST (inclusive → exclusive): a common mistake is simply multiplying the total by the rate — that overstates the tax. The correct method divides first: Base amount = Total ÷ (1 + rate ÷ 100); GST amount = Total − Base amount.
This is pure arithmetic, not tax advice. GST rates vary by good or service and change over time — always confirm the applicable rate for your actual transaction with the current official schedule.