Step 1 - Physical Measurements:
suit jacket size is determined by measuring the thickest part of
a man's chest in inches.
First, begin by measuring
just under your arms, across the chest, and over the shoulder blades.
When measuring, it is important to keep the tape measure parallel
to the floor. This will help to assure you are measuring the thickest
part of the chest area.
Second, it is also
helpful to take an overarm measurement. To take this measurement
place the tape measure over the outside of the arms across the thickest
part of the chest. Once you have this measurement subtract
7 inches to receive a corresponding chest measurement. Next,
compare this measurement with the chest measurement and take the
larger of the two.
Third, trouser sizes are
determined by measuring the waist at the belt line. In most cases,
the belt line will be found just on top of your hip bones.
Step 2 - Determine the Specialty:
In the clothing industry "specialty" refers to the length - extra short, short, regular, long, and extra long. Generally, a man's height will determine the specialty needed for the correct fit. As you can imagine, the taller you are the longer the coat you will need. Not only are the sleeves and the body of the coat longer, but the button stance on the front of the coat will be lower and the armsholes will be deeper. This keeps the coat balanced in proportion to your body while making the coat more comfortable to wear. If your height is:
5'4" or shorter - extra short
5'5" to 5'8" - short
5'9" to 5'11" - regular
6' to 6'2" - long
6'3" or taller - extra long
Step 3 - Determine the Model or "Cut"
The model of the suit is known by industry terms as the cut. A standard model (cut) generally will have a difference of 6 inches between the chest measurement and the waist measurement. This is commonly referred to as the "drop". For example, a 42 inch jacket will come with a size 36 waist trouser. The drop reduces to 5 and 4 inches the larger the chest size. Whether a standard cut suit will have 6, 5, 4 inch drop will vary by manufacturer. An athletic cut suit is more tapered in the body than a standard cut suit. It always has an 8 inch difference between the chest and waist regardless of chest size. A portly cut suit is the opposite of the athletic cut suit. It is cut fuller in the stomach area and will have a 4, 2, 0 inch drop depending upon the chest size.
These three steps will give you an excellent starting point to find the best fitting suit. Like all rules, there are exceptions that will vary by manufacturer as well as the man's physique.