business calculator
Add or remove GST from any amount with a custom rate.
Quick actions: Save inputs, view saved runs, print, share, or export results
Total amount
$110
Save this page to quote customers, prepare invoices, and isolate GST components from all-inclusive prices quickly.
Formula
Exclusive: total = amount x (1 + rate); Inclusive: pre-tax = total / (1 + rate)The calculator can add GST to a pre-tax amount or extract GST from a tax-inclusive total.
Step by step
Example
$100 before GST at 10% becomes $110 total with $10 GST.
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Summary
GST Total Amount
$110
GST Tax Component
$10
Pre-Tax Net Price
$100
GST Rate
10.00%
D3 visualization
Compare the base pre-tax amount with the GST component.
D3 visualization
Summary of GST base price, tax amount, and inclusive total.
Guide
Goods and Services Tax (GST) is a broad-based consumption tax applied to most goods and services. Like VAT, it is generally collected by businesses and remitted to the government. GST systems can be tax-exclusive or tax-inclusive, depending on local pricing conventions and invoice rules.
For commercial planning, the most important task is distinguishing whether a quoted figure already includes GST or whether GST must be added on top.
If the amount is tax-exclusive, add GST using:
$$\text{Total Amount} = \text{Base Amount} \times \left(1 + \frac{\text{GST Rate}}{100}\right)$$
$$\text{GST Amount} = \text{Base Amount} \times \frac{\text{GST Rate}}{100}$$
If the amount is tax-inclusive, recover the net amount using:
$$\text{Pre-Tax Amount} = \frac{\text{Gross Amount}}{1 + \frac{\text{GST Rate}}{100}}$$
$$\text{GST Amount} = \text{Gross Amount} - \text{Pre-Tax Amount}$$
These equations make GST isolation easy whether you start from a sticker price or a vendor quote.
A common practical issue is whether the customer sees GST included in the listed price. In some jurisdictions, consumer-facing prices must be inclusive. In other business-to-business settings, quotes are often GST-exclusive, with tax added later. Failing to identify the mode can lead to underbilling or margin erosion.
Registered businesses generally need to display the GST rate and GST amount separately on invoices. This creates a defensible compliance record and allows customers with business entitlements to claim tax credits where local law permits.
Inclusive pricing
A pricing model where tax is already embedded in the listed amount.
Tax credit
A reclaim or offset mechanism for eligible input taxes in business systems.
Gross amount
The final amount after GST or VAT has been applied.