# GST Calculator

URL: https://speedycalculator.com/calculators/finance/gst/
Last updated: 2026-10-25

> 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%.

## Inputs

- I want to
- GST rate
- Custom GST rate (%)
- Amount

## Results

- GST rate used
- Net price
- GST amount
- Gross price (incl. GST)

## Formula

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

## Explanation

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

- **I want to**
- **GST rate**
- **Custom GST rate**
- **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

FieldWhat to enterI want toChoose one: Add GST to a net price, Remove GST from a gross priceGST rateChoose one: Australia – 10%, New Zealand – 15%, Canada – 5%, Singapore – 9% …Custom GST rateIn %AmountAmount 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 amount6109101210151018102410

## 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.

## FAQ

**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.