Chest: Place measuring tape under your arms, keeping tape level measure around the fullest part of your chest / bust.

Waist: Measuring tape is placed at the narrowest point of your natural waist and measured around the body.

Hip: Place feet together and measure around the fullest part of your hips.

in inches 

Men's Size Chart:
Size | Chest | Neck | Sleeve
S | 36-38 | 14-14.5 | 32-33
M | 38-40 | 15-15.5 | 33-34
L | 42-44 | 16-16.5 | 34-35
XL | 46-48 | 17-17.5 | 35-36
XXL | 50-52 | 18-18.5 | 36-37

Women's Size Chart:
Size | Bust | Waist | Hips
XS | 32-34 | 24-26 | 34-36
S | 34-36 | 26-28 | 36-38
M | 36-38 | 28-30 | 38-40
L | 38-40 | 30-32 | 40-42
XL | 40-42 | 32-34 | 42-44

In cm 

Men's Size Chart:
Size | Chest (cm) | Neck (cm) | Sleeve (cm)
S | 91-96 | 36-37 | 81-84
M | 97-102 | 38-39 | 84-86
L | 107-112 | 41-42 | 86-89
XL | 117-122 | 43-44 | 89-91
XXL | 127-132 | 46-47 | 91-94

Women's Size Chart:
Size | Bust (cm) | Waist (cm) | Hips (cm)
XS | 81-86 | 61-66 | 86-91
S | 86-91 | 66-71 | 91-97
M | 91-97 | 71-76 | 97-102
L | 97-102 | 76-81 | 102-107
XL | 102-107 | 81-86 | 107-112