business calculator

GST Calculator

Add or remove GST from any amount with a custom rate.

Bookmark this GST calculator

Save this page to quickly calculate GST on receipts, business purchases, or invoices.

Saved runs

Inputs

Mode

Amount$GST rate%

Results

Total amount

$110

Pre-tax amount$100

GST amount$10

Summary

Key output metrics

GST Total Amount

$110

GST Tax Component

$10

Pre-Tax Net Price

$100

GST Rate

10.00%

D3 visualization

Pre-Tax vs Tax split

Compare the base pre-tax amount with the GST component.

Base Pre-Tax Price$100

GST Component$10

D3 visualization

GST Inclusive vs Exclusive Summary

Summary of GST base price, tax amount, and inclusive total.

Guide

How to understand and use this calculator

Exclusive vs. inclusive GST

Goods and Services Tax (GST) is a flat-rate consumption tax applied to sales. Depending on your audience, prices are presented either GST-exclusive (common in B2B transactions) or GST-inclusive (mandatory in many consumer retail markets).

Adding GST (exclusive) is straightforward: multiply pre-tax value by the tax percentage. Removing GST (inclusive) is different: divide the total by (1 + tax rate) to find the pre-tax base, then subtract that from the total to get the GST amount.

Related concepts

GST exclusive

A transaction price that does not include tax; tax is added at payment.

GST inclusive

A transaction price that already includes the tax amount.

FAQs

What is the formula to remove GST?

To extract GST from an inclusive total, divide by (1 + GST rate as decimal) to get the pre-tax base, then subtract this base from the total. For a 10% rate, divide by 1.10. For a 15% rate, divide by 1.15.

Why is GST shown separately on tax invoices?

Tax authorities require businesses to explicitly itemize GST so business buyers can claim tax credits for input tax paid on commercial purchases.

Formula

GST add or remove

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

How the calculation works

1Choose whether the amount includes tax.
2Use the GST rate as a decimal.
3Add tax for exclusive mode or reverse it for inclusive mode.
4Show pre-tax, GST, and total values.

Example

Example GST

$100 before GST at 10% becomes $110 total with $10 GST.

Related guides

Learn more about this calculation

Guide

GST and Sales Tax: Calculation and Compliance for Small Businesses

Calculate GST and sales tax amounts, understand tax-inclusive vs tax-exclusive pricing, filing requirements, and compliance tips for small businesses.

Guide

Markup vs Margin: Discount and Pricing Strategy for Profit

Understand the critical difference between markup and margin, how discount depth affects profit, and strategic pricing approaches to maximize revenue and profitability.

business calculator

GST Calculator

Add or remove GST from any amount with a custom rate.

Bookmark this GST calculator

Save this page to quickly calculate GST on receipts, business purchases, or invoices.

Saved runs

Inputs

Mode

Amount$GST rate%

Results

Total amount

$110

Pre-tax amount$100

GST amount$10

Summary

Key output metrics

GST Total Amount

$110

GST Tax Component

$10

Pre-Tax Net Price

$100

GST Rate

10.00%

D3 visualization

Pre-Tax vs Tax split

Compare the base pre-tax amount with the GST component.

Base Pre-Tax Price$100

GST Component$10

D3 visualization

GST Inclusive vs Exclusive Summary

Summary of GST base price, tax amount, and inclusive total.

Guide

How to understand and use this calculator

Exclusive vs. inclusive GST

Related concepts

GST exclusive

A transaction price that does not include tax; tax is added at payment.

GST inclusive

A transaction price that already includes the tax amount.

FAQs

What is the formula to remove GST?

Why is GST shown separately on tax invoices?

Tax authorities require businesses to explicitly itemize GST so business buyers can claim tax credits for input tax paid on commercial purchases.

Formula

GST add or remove

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

How the calculation works

1Choose whether the amount includes tax.
2Use the GST rate as a decimal.
3Add tax for exclusive mode or reverse it for inclusive mode.
4Show pre-tax, GST, and total values.

Example

Example GST

$100 before GST at 10% becomes $110 total with $10 GST.

Related guides

Learn more about this calculation

Guide

GST and Sales Tax: Calculation and Compliance for Small Businesses

Calculate GST and sales tax amounts, understand tax-inclusive vs tax-exclusive pricing, filing requirements, and compliance tips for small businesses.

Guide

Markup vs Margin: Discount and Pricing Strategy for Profit

Understand the critical difference between markup and margin, how discount depth affects profit, and strategic pricing approaches to maximize revenue and profitability.