When GST is added
GST amount = Original amount × GST rate ÷ 100.
The final price is the original amount plus GST.
Explore all tools →Calculate GST. Know your final price.
Quickly calculate GST on any amount. Choose a tax rate, add GST to a price, or find the GST already included in a total.
GST Calculator
Enter an amount to calculate tax instantly.
Choose GST rate
How should GST be calculated?
Results update automatically as you change the values.
How to calculate GST
GST (Goods and Services Tax) is calculated using the applicable tax rate on a product or service.
When GST is included
GST amount = Total amount × GST rate ÷ (100 + GST rate).
The GST portion is extracted from the given total.Important: This calculator provides a mathematical estimate. Confirm the applicable GST rate and tax treatment for your transaction.
Frequently asked questions
Which GST rates can I calculate?
You can calculate using 5%, 12%, 18% or 28%. Make sure you select the rate applicable to your goods or services.
What is the difference between adding and including GST?
Add GST to price when the entered amount excludes tax. Choose GST included in price when the entered amount already contains tax.
Can I copy my GST calculation?
Yes. Select Copy calculation to copy the amount before GST, tax amount and final total.