Its off by a bit. So I thought I'd dust off my old high school algebra book to do the calculations.
I copied my trading history and copied it into an excel spreadsheet.
I summed up all the transactions excluding shares I currently own, they give me
a total of R27,460.29 profit. Minus the transaction costs, R9,376.28, which gives me
R18,084.01. Multiplied by 0.3 to get the tax that must be subtracted, which gives me
R5,425.20 tax.
The net worth is R635,773.60 (at time I did this calculation). Subtracting tax, gives me
R630,348.40. Which is a 5.05% gain.
(phew)