It's impossible to know really. You won't get a valid answer cause without volatility it's a net net loss. Only time to place straddles are in high volatility environments, earnings, FOMC rate decisions etc. If a ticker goes sideways, without IV jumping there is no way to make substantial gains due to the losing side, and the fact that the underlying will likely reverse, causing net loss. If you were to get lucky and make gains after trade commissions, you might see 1-3%. Options are not priced for straddles to work or everyone would make money. It (the options chain) is just not set up that way. Then there are the Greeks to contend with. It's truly impossible..