Difference Between ER and LR Designations?


I was just wondering, what is the main difference between the ER and LR designation that Boeing uses for their 777?
Also, I know that the ER designation is used on some models of the 767, 747 & 777.

I know the LR designation stands for Longer Range & ER is Extended Range.

but my main question remains, what is the difference between the 2 designations.


Just a marketing gimmick. No significance other than to designate the ranges of the different models.


The 200LR has a higher MTOW, more powerful engines, and slightly tweaked aerodynamics (all of which are identical to the 300ER).


The LR can also take several extra fuel tanks in the cargo area in order to maximze the range. The landing gear system is redesigned to be able to take the extra weigth, and wing spar is strengthened.

It is much more than just a “marketing gimmick”.