What Is a GST Calculator?
A GST calculator is an online tool that calculates the Goods and
Services Tax applied to a product or service. It can help you add
GST to an original price or remove GST from an amount that already
includes tax.
The calculator separates the taxable value from the GST amount,
allowing businesses, buyers, sellers and freelancers to review
pricing quickly without performing the calculation manually.
Add GST
Calculate the GST amount and final price from a
GST-exclusive base amount.
Remove GST
Find the original taxable amount from a price that
already includes GST.
Custom GST Rate
Enter any percentage instead of being limited to
predefined GST rates.
How to Add GST to an Amount
To calculate a GST-inclusive price, multiply the original amount
by the GST rate and divide the result by 100. Add the GST amount
to the original price to get the final total.
GST amount:
Original Amount × GST Rate ÷ 100
GST-inclusive total:
Original Amount + GST Amount
For example, if the original amount is 1,000 and the GST rate is
18%, the GST amount is 180. The final GST-inclusive price is
therefore 1,180.
How to Remove GST From a Total Amount
Removing GST requires a reverse calculation. You should not
simply subtract the GST percentage from the total because the
percentage was originally applied to the base amount.
Original amount:
GST-Inclusive Amount ÷ (1 + GST Rate ÷ 100)
GST amount:
GST-Inclusive Amount − Original Amount
For example, if a total price of 1,180 includes 18% GST, the
original amount is 1,000 and the included GST amount is 180.
How to Use This GST Calculator
Select Add GST or Remove GST
Choose Add GST for a tax-exclusive amount or Remove GST
when the entered total already contains GST.
Choose your currency
Select the currency you want the calculator to use when
displaying the final result.
Enter the amount
Add the price before GST or the total GST-inclusive
amount, depending on your selected calculation mode.
Enter the GST rate
Select a quick percentage or manually enter a custom GST rate.
Review the result
The calculator displays the original value, GST amount,
applied rate and final total.
GST rates and tax rules can differ by country, product,
service and transaction type. Confirm the applicable rate
with the relevant tax authority or a qualified tax
professional before preparing an official invoice or tax return.
Frequently Asked Questions
What does GST stand for?
GST stands for Goods and Services Tax. It is a
consumption-based tax applied to eligible goods and
services in countries that use a GST system.
How do I calculate GST on a price?
Multiply the original price by the GST percentage and
divide by 100. For example, GST on 1,000 at 18% is
1,000 × 18 ÷ 100, which equals 180.
How do I remove GST from an inclusive amount?
Divide the GST-inclusive amount by 1 plus the GST rate
expressed as a decimal. At 18% GST, divide the total by
1.18 to find the original amount before GST.
Can I enter a custom GST rate?
Yes. You can enter any GST percentage between 0% and
100%, or select one of the quick rate buttons provided
in the calculator.
Is GST calculated on the original price?
When GST is added to a tax-exclusive amount, it is
calculated as a percentage of the original taxable price.
Does this calculator provide tax advice?
No. This calculator provides general mathematical
estimates only. Applicable GST rates, exemptions,
credits and filing requirements should be confirmed with
the relevant tax authority or a qualified professional.