The size of a suit is usually indicated by a double-digit number, followed by a letter. The first two digits indicate the chest size of the suit, while the letter denotes the length of the coat. The pant size can also be estimated from these dimensions as well. The difference between a 44S and a 44R suit is that the first suit is a "short" length, while the second is deemed a "regular" length.
The two-digit part of a suit's size denotes the chest circumference in inches, so a 44S and a 44R size of the same suit share the same chest dimensions. Most suit makers manufacture coats from size 40 through 54. If your chest size falls outside of those dimensions you will usually have to have a suit custom-made or have to buy from a speciality retailer, such as a big and tall store. European designers generally tailor their suits trimmer than American makers, so if you normally wear a 44 you may have to size up to a 46 in a European-made coat.
Suit makers apply letters to their coat's sizes to denote the length of the coat. "S" is used to denote a short length, intended for men between 5-foot-5 and 5-foot-7 in height. "R" is used for regular length coats that generally fit men between 5-foot-8 and 5-foot-10. The letter "L" is applied to long coats, which are generally intended for men standing between 5-foot-11 and 6-foot-2. Every person's body is made slightly different and in the cases of a person with a disproportionately-sized torso, these height guidelines may not apply. The general rule of thumb is that the bottom of a coat should cover a man's buttocks but not fall any lower.
The simple 44S or 44R size designation can also tell you information about the trousers included with the suit. You may hear your suit salesman mention the term "drop" in reference to the trousers size. Most suits have a 6-inch drop, meaning that the trousers' waist is 6 inches smaller than the chest dimension. Athletic and slim fit suits may have a larger drop, giving the suit a smaller waist size; conversely, husky-size suits may have a smaller drop, giving the suit a proportionately larger waist size.
Suit trousers are shipped from the factory with an unfinished hem, unlike casual trousers that have a finished hem. The final alteration of the length can be handled by a tailor, allowing you to choose between a plain or cuffed bottom. Suit makers offer coats in different lengths due to the complexities of altering a garment with a lining, an obstacle that does not exist when altering the length of trousers.