I have made a simple excel spreadsheat... Just work on the share price. Colums - Underlying Buying Price, Underlying selling price, Units, Amount (Buying* Units), Fixed cost(R 136.8), Variable cost (sum Buy*Units+Sell*units)*0.004 , Total cost (Fixd cost+Variable cost) , Profit /Loss ( Sum (selling*Units - Buying*units) - Total Cost. On this can work out day trading for short an long. Than extra colums - day , interest (sum purchase* interest rate) , total interest ( daily interest * days) , Total profit loss ( Sum Profit /loss - Total interest ) So one can play around of looking the effect of holding the share for differnt periods of time. And finaly just the % colum (sum Selling - Purchase)/ Purchase - to see what share needs to rise or fall to make profit. From here one can extend extra so that you only put in figures ( buying and selling at underlining... to immediate work out what if you wrong...for stop loss and proftit on 4 or 5 different scenario's that can happen. Although not bringing in divivdends it help me a lot in making decisions.