2021 Charts, page-3298

Krugerrrands, any capital gain is taxed with the top rate your earnings stack up to. This is called your marginal tax rate.
Current marginal tax rates in Oz are:

0% for income up to $18.2k, 19% up to $45k, 32.5% up to $120k, 37% up to $180k and 47% for anything above.

I am sorry to tell you your the rate applicable to your CGs won't be averaged down to your effective one. They will be taxed with the highest rate applicable to the notch they fall in.

In any case,@GCar took the highest rate to make the analysis as visible as possible. Needless to say, if you earn less than $18k a year (capital gains included), you won't have anything to worry about and the analysis won't be relevant to you. Conversely, high rollers will pay much attention to this as 47% is quite a bite.