Speedy Calculator

GST Calculator

Finance Updated October 25, 2026

Quick answer

The GST calculator adds goods and services tax to a net price or removes it from a GST-inclusive price, for any GST rate – Australia 10%, New Zealand 15%, Canada 5%, Singapore 9%, India 5–40%.

$
GST rate used
— %
Net price
$ —
GST amount
$ —
Gross price (incl. GST)
$ —

Goods and services tax is a value-added tax charged at each stage of supply. Businesses registered for GST charge it to customers and claim back the GST they pay on purchases.

How to use the GST Calculator

  1. I want to
  2. GST rate
  3. Custom GST rate
  4. Amount

Results update as you type, and every field accepts the units shown in its menu.

How it works

Choose whether to add or remove GST, the rate and the amount.

Tips

  • Tax figures here are estimates for planning – your actual tax depends on credits, deductions and local rules.
  • Check the tax year and filing status before you rely on a result.
  • Use gross (before-tax) figures unless a field asks for take-home pay.
  • When in doubt, confirm with the tax authority’s own calculator or a tax professional.

Common mistakes to avoid

  • Confusing marginal and effective tax rates.
  • Adding sales tax to a price that already includes it.
  • Forgetting payroll taxes (Social Security and Medicare) on wages.

Inputs explained

Field What to enter
I want to Choose one: Add GST to a net price, Remove GST from a gross price
GST rate Choose one: Australia – 10%, New Zealand – 15%, Canada – 5%, Singapore – 9% …
Custom GST rate In %
Amount Amount in your currency

What each result means

  • GST amount = [Net price]×[GST rate used]÷100
  • Gross price (incl. GST) = [Net price] + [GST amount]

Example values

How the main result changes when Custom GST rate changes and everything else stays at the example values above:

Custom GST rate (%) GST amount
6 10
9 10
12 10
15 10
18 10
24 10

Formula

Add GST: gross = net × (1 + rate); GST = net × rateRemove GST: net = gross ÷ (1 + rate); GST = gross − net

Worked example

Inputs — I want to: Add GST to a net price; GST rate: Australia – 10%; Custom GST rate: 12 %; Amount: $100.
Results — GST rate used = 10 %; Net price = $100.00; GST amount = $10.00; Gross price (incl. GST) = $110.00.

Frequently asked questions

How do I calculate GST?

Multiply the net price by the GST rate.

How do I remove GST from a price?

Divide the GST-inclusive price by (1 + rate).

What is the GST rate in Australia?

10%.

What formula does the GST Calculator use?

Add GST: gross = net × (1 + rate); GST = net × rate.

Cite this calculator

Speedy Calculator. (2026). GST Calculator. Speedy Calculator. https://speedycalculator.com/calculators/finance/gst/