Starting a business can be daunting with bookkeeping, GST and ABNs. Take Scott, for instance. He’s just started a carpentry business, which most likely means he’s a carpenter that’s decided to freelance.
He got an ABN (Australian Business Name) and registered for GST, and is now confused between GST and income tax.
To simplify the GST issue.
If you are registered for GST you now become a tax collector for the Government, so every time you invoice a client, you need to add 10% to the invoice.
This 10% extra money belongs to the ATO. It’s not yours to keep. SO put it in a separate bank account.
Every time that you buy a product/service for your business you will see on the suppliers invoice or cash receipt how much GST they have charged you
Rather than sending the 10% on each transaction to the ATO, you lodge a Business Activity Statement BAS (normally each quarter) and tell the ATO that you have COLLECTED $xxx in GST, and you tell them you have PAID out $yyyy in GST
So if you’ve collected more than you’ve paid out in that reporting period then you need to give the ATO their money back
If you’ve paid out more than you’ve collected at the end of the reporting period, the ATO needs to give YOU money back
i.e if you’ve collected $3000 in GST, and paid out (to your suppliers etc) $1000 in GST you owe the ATO $2000
if you’ve collected $1000 in GST and paid out $1500 in GST then the ATO will REFUND $500 in that reporting period
INCOME TAX
This is different. Quite simply you get taxed on all your TOTAL income less any BUSINESS expenses.
If you earn $70k as a carpenter, another $20k from rental properties, and $10k from shares/stockmarket investments, then that’s a total of $100k (the GST part was never yours and is not included here)
If it’s cost you $30k to run your carpentry business (suppliers, subbies, tools etc) and $10k to run your rental properties (loans, maintenance etc) then your expenses would be $40k – so your taxable income would be $60k (less other things like medicare, etc etc, )
This is why small business owners need bookkeepers – to track the GST and income / expenses for your business, or help you set up a bookkeeping system so that you can do the same.
We are not tax agents and cannot give specific advice. Before taking any direction please speak to a professional registered tax agent and do not rely on the example above.

In other words, your supplier has just increased the invoice by 10% – so do you go back and question the invoice amount and request that they issue the invoice without the GST component?
The GST is only one component of tax that you need be concerned about. Unless you’ve started your new venture as a hobby, would it be fair to say that you are looking at expanding your income?

