Egg grading system

There are three consumer grades for eggs in USA. Grade AA, A, and B. The grade is determined by the interior quality of the egg and the appearance and condition of the egg shell. Eggs of any quality grade may differ in weight (size).
The freshest and highest quality eggs will receive a Grade AA. Very high quality eggs will receive a Grade A. Grade B eggs are usually used for breaking stock (liquid eggs) and baking, depending on the number of defects.
In Europe, eggs are graded by weight and quality. Class A eggs are graded by weight: XL – more than 72 g, L – 63-72 g, M – 53-62 g, S – less than 53 g. Class B eggs are those that do not meet the quality thresholds of class A eggs, or they are Class A eggs that have been downgraded. Only packing centers can grade and pack eggs, and label their packs.