There are 6 U.S. grading standards provided for onions excluding the Bermuda-Granex-Grano and Creole types. U.S.1, U.S. Export, U.S. Commercial, U.S. No.1 Boilers, U.S. No.1 Picklers, and U.S.2.  U.S. grading standards for Bermuda-Granex-Grano provide for three standards, U.S.1., U.S. Combination, and U.S.2.

U.S.1 consists of onions with similar characteristics which are mature, fairly firm, well shaped, and free from wet scald, sunburn, doubles, bottlenecks, seedstems, roots, sprouts, freezing, cracked fleshy scales, watery scales, dirt, disease and insects.

Unless otherwise stated the diameter should not be less than 1 1/2.  Yellow, brown, and red onions shall have 40% or more, and white shall have 30% or more by weight of the onions in any lot 2 inches or larger in diameter.