Neck (Shirt)
Neck measurement is commonly used for sizing men’s dress shirts. Many dress shirts sold in the U.S. actually use the neck size in inches as the “size.” Wrap the measuring tape around the base of your neck, going around your Adam’s apple. Ensure that the tape is consistently level and that you’re not wrapping the tape too tightly around your neck. This measurement is your true neck measurement. For your dress shirt neck measurement, add a half inch to a round number (i.e. 14 inches should be rounded up to 14.5 inches) or round up to the nearest half inch (i.e. 14.25 should be rounded up to 14.5).

Chest
Place one end of the tape measure at the center of your chest. Wrap it around your body, keeping the tape parallel to the floor.

Waist
Most clothing lines use the measurement of the “natural waist” for their size guides. To measure your natural waist, you want to find the narrowest part of your waist, located above your belly button and below your rib cage.

Inseam
The inseam is the distance from the uppermost part of your thigh to your ankle. It is easiest to measure the inseam based on a well-fitting pair of pants. Measure from the crotch to the cuff on the inside seam of the leg. The number of inches, to the nearest ½”, is the inseam length. It’s best to measure your inseam with a pair of shoes on so that you can ensure the hem hits at the right point on your shoe.

How do I figured out what my suit size is?
Suit and sport coat sizes have one number and one descriptive word (for example, 38 short, 40 regular, 42 long). The number refers to your chest measurement, and the descriptive word refers to the length of the jacket.

Suit Lengths
Short (S) - Males Height 5'4" to 5'7 1/2"
Regular (R) - Males Height 5'8" to 6'2"
Long (L) - Males Height 6'2 1/2" to 6'5"
X-Long (XL) - Males Height6'5 1/2" and up