You don’t get taxed twice.
If you’ve held the investment >12 months then the CG is discounted by 50%. This amount is then added to your other earnings to determine your taxable income.
So, If you had a $20K CG and $30K in other earnings your new taxable income would be $40K.
HWD007 and RodC are both right, but have possibly missed – or at least not mentioned – the most important part….
CGT ( Capital Gains Tax ) is only payable WHEN YOU SELL.
Therefore, if your strategy is “buy and hold” ie never sell, then you will NEVER pay CGT.
Please note that there are some other instances that may trigger a CGT event, such as in certain situations changing or transfering the ownership of a property ( or shares for that matter ). For example transfering the property from “Ms Elvis” to “Graceland Pty Ltd”, or “The Presley Family Trust” – ie from an individual to a company or trust, can trigger CGT.
As always, check with your accountant if in doubt.