User:Julian Grybowski/suit size

The suit, being an essential piece of most mens' wardrobe (either for work or for special occasions), is widely available as ready-to-wear clothing, in addition to forms tailored to the customer's individual measurements (bespoke and made-to-measure). Because of this, a number of standard sizes have been developed as a way of fitting suits to most individuals' bodies.

Jacket
Chest size, measured in inches, is the most common form of jacket sizing available in North America and the UK. In it, the circumference of the customer's trunk at the __________ is used as a baseline measurement. Other elements (overall length, shoulder width, shape, and sleeve length) are based on the cut of the garment, specific variants of which are determined by the manufacturer. The most common variants are for different heights, and usually include: Regular, the "standard" cut for individuals between (roughly) 5'6" and 6' tall; Short, for individuals shorter than 5'6"; and Long, for individuals taller than 6'. These height variants are signified by the first letter of their name after the chest measurement: for example, a jacket for an individual with a 40" chest of "Regular" height is written as 40R. Some lines also take into account physical build: in these cases, "Regular" signifies a jacket cut for an "average" build, "Athletic" for a more tapered fit, "Slim" for an overall narrower line, and "Executive" or "Portly" for a rounder silhouette. These variants are indicated more idiosyncratically, and may vary widely between manufacturers.

In any instance, individual measurements are likely to vary at least slightly from the sizes indicated above, and to ensure a proper fit, the jacket may require additional tailoring after purchase.

Trousers
For the trousers paired with the jacket, the waist size is (for a standard build) generally six inches smaller than the chest size, such that a jacket for a 40" chest will be paired with trousers for a 34" waist, a 42" chest with a 36" waist, etc. Variants for differring body types (as discussed above) will have larger or smaller waists, as dictated by the cut. The bottoms will usually be left unfinished, to be hemmed (usually for free at point-of-sale) to the wearer's needs, either straight or with turn-ups (cuffs) according to personal preference.

Suit separates are an alternative method employed at some retailers, in which the trousers are chosen separately from the jacket, pre-hemmed to a specific length. This is helpful to individuals whose waist sizes do not match those commonly included with the jacket of their size.

Waistcoat
As three-piece suits have become comparatively rare since World War II, they are not widely found at retail. However, when they are available, they are usually designed to accommodate a girth identical to the waist of the included trousers. (Length is generally designed to agree with the cut of the jacket, though customers with a particularly long or short torso are likely to require a specially-made garment.)

Japan
Men's clothing sizes in Japan are governed by the JIS L 4004 Standard. It is thus used by Japanese manufacturers of suits for the ready-to-wear market.

In this system, there are two primary variables. One is the nearest approximation to the wearer's height in centimeters, specified by a number (most commonly 3 through 9). This number increases in 5-centimeter increments, such that 3 corresponds to a height of 160 cm, 4 to 165 cm, 5 to 170 cm, and so on. This measurement determines the length of the jacket. The other variable is the body type, which determines the cut of the jacket and (more importantly) the size of the trouser waist. For example, a body type of "A" assumes a difference of 12 centimeters between chest and waist measurements, "AB" a difference of 10cm, and "BB" a difference of 6cm. Thus, waist size and jacket length increase with an increase in height measurement, while waist size and jacket girth increase with succeedingly expansive body types.

The standard formulation for this sizing system can be seen below:

Not all types specified by the standard are available everywhere; the most common types are Y, A, AB, BB, and (to some extent) E, with most stores carrying a subset of the less common ones. Of these less common types, AEON stocks only JY, while Izumiya stocks YA and BE. NOTE: find out about Daiei, Ito Yokado, etc.

Patterns at height designations "2" (155cm) and "10" (195cm) are also available, but are generally not made in large quantities and must be special ordered.

Refs: Illustration of sizing system, plus how to find the most appropriate size