Before every protective put trade it is possible to calculate
your anticipated maximum loss. Use the formula: (stock price
minus strike price) plus option price. For example, suppose you
will pay $30.00 for your stock, and you want no more than a $3.50
loss on the position. Then you would choose the $27.50 strike
put which costs $1.00. Following the formula, you take your
stock price ($30.00) and subtract the put