Athletic fit is larger in the shoulders, chest, waist and arm holes and is longer in the arms and body.

MEN'S SHORT SLEEVE SHIRT SIZE CONVERSION CHART
Tailored Fit
Size	XXS	XS	S	M	L	XL	XXL	XXXL	XXXXL
Chest	36"	38"	40"	42"	44"	46"	48"	50"	-
Back Length	27 1/2"	28 1/2"	29 1/2"	30 1/2"	31 1/2"	32 1/2"	33 1/2"	34 1/2"	-
Sleeve Length(shoulder to cuff)	8 1/4"	8 1/2"	8 3/4"	9"	9 1/4"	9 1/2"	9 3/4"	10"	-
Standard Fit
Size	XXS	XS	S	M	L	XL	XXL	XXXL	XXXXL
Chest	37"	39"	41"	43"	45"	47"	49"	51"	-
Back Length	26 1/2"	28 1/2"	29 1/2"	30 1/2"	31 1/2"	32 1/2"	33 1/2"	34 1/2"	-
Sleeve Length(shoulder to cuff)	8 1/2"	8 3/4"	9"	9 1/4"	9 1/2"	9 3/4"	10"	10 1/4"	-
Athletic Fit
Size	XXS	XS	S	M	L	XL	XXL	XXXL	XXXXL
Chest	-	40"	42"	44"	46"	49"	52"	55"	58"
Back Length	-	28 3/4"	29 3/4"	30 3/4"	31 3/4"	33 1/4"	34 1/4"	35 1/4"	36 1/4"
Sleeve Length(shoulder to cuff)	-	9 1/4"	9 1/2"	9 3/4"	10"	10 1/4"	10 1/2"	10 3/4"	10 3/4"
Relaxed Fit
Size	XXS	XS	S	M	L	XL	XXL	XXXL	XXXXL
Chest	-	-	42 1/2"	44 1/2"	46 1/2"	48 1/2"	50 1/2"	52 1/2"	54 1/2"
Back Length	-	-	29 1/4"	30 1/4"	31 1/4"	32 1/4"	33 1/4"	34 1/4"	35 1/4"
Sleeve Length (shoulder to cuff)	-	-	9 1/2"	9 3/4"	10"	10 1/4"	10 1/2"	10 3/4"	10 3/4"

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Conversion sizes may vary.