This is a cotton, true to size shirt. Please check sizing below. What I would suggest:
find your own favorite long sleeve shirt from your closet. Measure across the chest, under the arms, and then choose the size closest to that shirt. It might be a size down or up than you are used to!
Measured one inch below armhole.
Measured from high point of shoulder from the front.
Measured from high point of shoulder to finished hem at sleeve.