The Charlie Sweater has a nice amount of stretch to it, and side slits for movability.
True to size fit.
Measurement across the bust, with the garment laying flat:
XS 20" // Small 21" // Medium 22" // Large 23" // XL 24" // 2XL 25" // 3XL 25.5"
Measurement from the armpit to the bottom hem all sizes 18"