Australian GST Credit Calculator

Work out the GST hidden in your business purchases. This is a calculation aid: it does not decide whether a particular credit is claimable.

How the estimate works

For a GST-inclusive purchase price that contains 10% GST, the GST component is the total divided by 11. For example, A$1,100 inclusive contains A$100 GST.

When a GST credit may be available

If you are registered for GST, you can generally claim credits for eligible business purchases, as long as the requirements are met. Conditions include business use, GST being included in the price and holding the right tax documentation. A purchase that is private, input-taxed or otherwise ineligible may not produce a claimable GST credit.

Worked example: a Hobart builder’s purchases

A Hobart builder buys $5,500 of timber including GST for a client job. The GST component is $5,500 divided by 11, which is $500. He holds a valid tax invoice and the timber is used entirely for the business, so he claims the full $500 credit on his BAS. The next month he buys a $2,200 laptop that he uses 80% for business and 20% for personal browsing. The GST component is $200, but he can only claim the business share, which is $160. Try both figures in the calculator above. Before claiming anything, run each supplier invoice through the Australian tax invoice checklist to make sure the paperwork supports the claim.

Practical tips for claiming credits without trouble

Keep every tax invoice for purchases of $82.50 or more, because you generally cannot claim without one. Work out the business-use percentage honestly at the time of purchase rather than guessing at BAS time. Do not claim GST on GST-free purchases, since there is no GST in the price to claim, or on input-taxed supplies. Claim the credit in the BAS period when you are entitled to it under your accounting method, and keep records for five years. The Australian GST calculator can double-check the sales side of the same BAS.

Important distinction

This calculator works out the maths. It does not decide eligibility, apportionment or timing for your BAS. Keep the relevant records and check the ATO guidance.

Frequently asked questions

Can I claim GST on everything I buy for the business?

Only on eligible purchases. The purchase must include GST, be for business use, and meet the documentation rules.

What if I lose the tax invoice?

Ask the supplier for a copy. For purchases of $82.50 or more including GST, you need a valid tax invoice to support the claim.

Can I claim GST on things I bought before registering?

Generally you can only claim credits from your registration date, though there are rules about stock and assets you hold when you register. Get advice if this applies to you.

Where do I claim the credit?

GST credits are claimed on your BAS at the GST on purchases label. The net figure flows through to what you pay or get refunded.

Australia BAS GST Calculator · GST Component Calculator · ATO