You've found the perfect sweater pattern. It's just challenging enough to keep your interest. You think you'll be able to wear it a good part of the year for many occasions. The yarn is something you can afford.
But before you can begin, you need to answer one question: What size do I make?
Studying the size information, you note there are 4 sizes: small, medium, large, and extra large. Usually you wear a medium. But wait. The pattern states for the medium size, the finished chest measurement is 50". That does not seem right at all, you think. In fact, it seems like the sweater will be way too large!
Before deciding the pattern is wrong or what size you'll make, there are a number of considerations to take into account. Ask yourself how you like your sweaters to fit. Do you like them tight? If you do, perhaps you will want to choose a smaller size. Do you like them loose? Do you layer them with lots of other pieces or with just a camisole underneath? Do you wear your cardigans more like jackets or buttoned up as a top? Keep all of your preferences in mind as you consider the size.
Generally a sweater is not worn skintight. The difference between your bust measurement and the finished chest measurement of a sweater is referred to as "ease." Some garments have more ease than others, depending upon a number of factors.
The overall design of the garment dictates the amount of ease. Some are intended to be more form fitting, such as a shell. Others are meant to be roomier or "slouchy" in style.
Also, keep in mind that cardigans are worn over other clothing. They were designed to accommodate the extra bulk that is taken up by the clothing worn under the cardigan. Therefore, you will likely see a larger finished chest measurement for cardigans than pullovers.
Finally, sweaters that use very bulky yarns have more ease. The yarn itself literally takes up some of the allotted ease of the garment.
If in doubt, measure a sweater that fits you well which is similar in style and weight to the one you plan to make if at all possible. You might be surprised to find the finished chest measurement of that sweater is larger than you think!