you are here: sizing
hey dave- 
the shirts are fitted and tend to fit a bit small (especially the women's),
so if unsure i suggest ordering a size bigger.  so does dave.
 
 
men's size
 
S
M
L
XL          XXL                     XXXL
chest (inches)
34-36
38-40
42-44
46-48    pretty big         big
waist (inches)
30-32
32-33
32-34
36-38    pretty big         big

 

women's size  (we can also print women's slogans on mens size shirts)
 
S
M
L
XL
chest (inches)
30-32
32-34
36-38
40-up
waist (inches)
25-26
27-28
30-32
34-up

 

chest
measure under your arms around the fullest part of the bust. be sure to keep tape level across back, and comfortably loose. 
and hey, relax, there's no pressure here.
 
waist
measure around natural waist with a loose tape.  natural waist includes that part you wish you didn't have.