GST Calculator
Add GST to a base amount or remove GST from a tax-inclusive price at a chosen rate.
How to use GST Calculator
Three quick steps — no sign-up needed
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Step 1
Choose Add GST or Remove GST
Add GST builds tax on top of a net amount; Remove GST backs tax out of a gross (inclusive) price.
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Step 2
Enter amount and GST rate
Type the money amount and the GST percentage that applies (for example 18% where that rate is used).
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Step 3
Read net, tax, and gross
Use the breakdown for invoices, quotes, and price lists - then match your local tax rules.
About GST Calculator
GST Calculator adds or removes Goods and Services Tax from a price at a rate you choose. Freelancers and small businesses search "GST calculator online", "add GST", and "remove GST from amount" when preparing quotes or checking tax-inclusive retail prices.
Select Add GST or Remove GST, enter the amount, and set the GST rate (%). Add mode treats your input as exclusive (net) and computes tax and gross. Remove mode treats input as inclusive and splits out the tax component and net amount.
Taxability, exemptions, place-of-supply rules, and e-invoicing requirements differ by country and product type. This math helper does not file returns or decide whether GST applies to a specific supply.
Always align final invoices with your accountant and the tax authority rules that govern your business.
Benefits of GST Calculator
Frequently asked questions
How do I add GST to a price?
Choose Add GST, enter the net amount and rate; the tool computes tax and the gross total.
How do I remove GST from an inclusive price?
Choose Remove GST and enter the gross amount and rate to back out net and tax.
Which GST rate should I use?
Use the rate that applies to your supply under local law - the calculator does not choose it for you.
Is this valid as a tax invoice?
No. It only does arithmetic. Official invoices must meet legal format rules.
Is this tax advice?
No - educational calculation only. Confirm with a qualified tax professional.