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GST Calculator Australia

The most accurate BAS calculator online to compute your GST obligations for your Business Activity Statement.

GST Calculator for Australian Small Business (BAS)

Our free GST calculator for Australia helps small businesses estimate their Goods and Services Tax (GST) liability for their Business Activity Statement (BAS). Enter your sales and purchases to see how much you need to pay or will be refunded.

Step 1 of 4: Setup

Setup

Sales

Purchases

Result

Setup Your BAS Period

Select your reporting frequency and accounting method.

How to Prepare Your BAS in 3 Steps

Preparing your Business Activity Statement involves summarizing your business transactions for the reporting period.

1

Collate Sales

Gather all your sales invoices. Add up the total sales and calculate the GST you have collected (typically sales amount / 11).

2

Collate Purchases

Gather all receipts for business expenses. Add up the GST credits you can claim from these purchases (GST paid / 11).

3

Calculate Net GST

Subtract the total GST credits (from purchases) from the total GST collected (from sales). The result is what you owe the ATO or what they owe you.

Frequently Asked Questions

Calculations Verified

Based on official ATO GST Calculation Rules

Last System Audit

March 31, 2026

Expert Methodology

How We Calculate GST

This tool uses the standard 10% Goods and Services Tax (GST) rate as legislated in Australia. It accurately handles both 'Add GST' (Inclusive = Base × 1.1) and 'Extract GST' (GST = Total / 11) formulas.

Disclaimer:This tool provides estimates for educational purposes only. It is not financial advice. While we strive for 100% accuracy, individual circumstances such as tax-free status or specific BAS requirements may affect your final figures. Always consult with a registered tax agent.