* Chester Bennington (vocalist) - Born March 20, 1976. Age at formation: 20 years old.
* Mike Shinoda (rapper, vocalist, guitarist, pianist) - Born February 11, 1977. Age at formation: 19 years old.
* Brad Delson (lead guitarist) - Born December 1, 1977. Age at formation: 18 years old.
* Rob Bourdon (drummer) - Born January 20, 1979. Age at formation: 17 years old.
At the time of their first formation, the members' ages ranged from 17 to 20 years old, with Brad Delson being the youngest and Mike Shinoda being the oldest. It's worth noting that the band underwent several lineup changes in its early days before solidifying this primary group of musicians.