There is some overlap when defining bisexual and pansexual orientation; however, there are important differences between the two identities.
Bisexual people are attracted sexually and romantically to both males and females, and are capable of engaging in sensual relationships with either sex. Despite being able to form meaningful, lasting relationships with both sexes, bisexual individuals may, to a small or large degree, have a preference for one sex over the other.
Similarly, pansexual people may be sexually attracted to individuals who identify as male or female; however, they may also be attracted to those who identify as intersex, third-gender, androgynous, transsexual, or the many other sexual and gender identities. The latter distinction is what draws the line between pansexuality and bisexuality. People who self-identify as pansexual do so with purpose, to express that they are able to be attracted to various gender and sexual identities, whether they fall within the gender binary or not. Recognition of the existence of different genders and sexualities is a major aspect of pansexual identity. Pansexual people are bisexual, in-fact; however, bisexuality does not place the same emphasis on sexual and gender identity awareness, but more simply indicates attraction to the two (generally accepted) biological sexes.
The differences between the two sexual identities are undermined by the fact that some people who consider themselves pansexual identify themselves as bisexual out of convenience, as it’s a more widely known sexual identity. In addition, some people who consider themselves bisexual may be open to dating someone who falls outside the gender binary.