The delta of a deep out-of-the-money forex option will be closer to zero, the delta of an at-the-money forex option will be near .5 (the probability of exercise is near 50%) and the delta of deep in-the-money forex options will be closer to 1.0. In simplest terms, the closer a forex option's strike price is relative to the underlying spot forex rate, the higher the delta because it is more sensitive to a change in the underlying rate.