How to Use This GST Calculator
Our Australian GST calculator is designed for simplicity and accuracy. Start by entering the amount you want to calculate in the input field. Then select whether you're working with a GST-exclusive amount (where you need to add GST) or a GST-inclusive amount (where you need to extract the GST component). Click "Calculate GST" to see your results instantly, including the original amount, GST amount, and total.
For GST-exclusive calculations, the calculator multiplies your base amount by 1.1 to determine the total including GST. For GST-inclusive calculations, it divides your total by 11 to find the GST component, giving you both the net amount and the tax portion. These are the official formulas used by the Australian Taxation Office.
Frequently Asked Questions
When should I use GST Exclusive vs GST Inclusive?
Use GST Exclusive (Add GST) when you have a base price and need to calculate the total including GST – common when creating invoices or quotes. Use GST Inclusive (Remove GST) when you have a total price and need to determine how much GST is included – useful when reviewing receipts or checking competitor prices. Most retail prices in Australia are displayed GST-inclusive, while business-to-business quotes are often GST-exclusive.
Is the GST calculation always exactly 10%?
Yes, Australia has a flat GST rate of 10% on all taxable supplies. Unlike some countries with multiple tax rates, Australian GST is straightforward. However, not all goods and services attract GST. Items like basic food, medical services, and some educational courses are GST-free. Our calculator uses the standard 10% rate and also offers a 0% option for GST-free items to help you with all your calculations.
Can I use this calculator for my business BAS?
While our calculator provides accurate individual GST calculations, we recommend using it as a verification tool alongside your accounting software for Business Activity Statement preparation. It's perfect for double-checking invoice amounts, verifying supplier charges, or understanding GST on specific transactions. For official BAS lodgement, ensure you maintain proper records and consider consulting with a registered BAS agent or accountant.