The 757-200 is the definitive version and forms the majority of 757s sold. It shares its fuselage cross section with the smaller 727 and 737. Boeing positioned the plane above the 737 and as an eventual replacement for the 727.
During development, the 757-200 was originally meant to be a little shorter in length. In the end it was positioned not only above the 737, but also the 727. This variant can carry 228 passengers in a single class. However, with a seat pitch of 29 inches it can carry a maximum of 234 passengers. This configuration is the FAA limit for the aircraft due to emergency exit rules.
The 757-200 was available in two different door configurations. One version used three standard doors per side with an additional, smaller door aft of the wing on each side for emergency evacuations. All eight door locations are equipped with inflatable evacuation slides. The alternate version is equipped with three standard doors per side (two towards the front and one at the aft of the cabin) with two "plug-type" over-wing exits per side replacing the smaller door aft of the wing.
Other versions such as a 757-200ER were proposed, but never launched. Improvements such as winglets are offered for those upgrading their fleets. These enhanced 757-200s are sometimes referred to as 757-200ER aircraft