Calculating the profit or loss for an individual stock transaction requires simple subtraction to determine the difference in price. Aggregate differences from multiple stock transactions represent your overall profit or loss. You can add all your stock purchase costs and subtract this number from your total sales, but this only shows your overall profit. It's better to figure the profit or loss from individual stocks first to obtain information on each transaction before calculating the overall total.

Add the total cost of purchasing one of the stocks. This should include the total price paid per share and any broker fees. For example, if you purchased 100 shares of stock ABC for $60 per share, and you paid a $25 broker fee, your total cost is $6,025.

Subtract the total purchase paid in Step 1 from the total sales price to figure profit or loss. If the result is negative, you incurred a loss; if it's positive, you made a profit. In the example, if you sold the 100 shares of stock for $55, and you paid a $25 broker fee, your net is $5,475. Subtract $6,025 from that amount for a loss of $550.

Repeat the above series of calculations for each stock you sold to determine the profit or loss on each transaction.

Add each profit or loss to calculate your overall profit. Remember that negative numbers are subtracted from the total. For example, if you made a profit $700 on one transaction and you lost $550 and $300 on two transactions, your loss on the multiple transactions was $150.