This page lists forms of the 断定助動詞 "dantei jodoushi", sometimes called the Japanese "copula". The tables are arranged in increasing order of politeness, with forms having approximately similar politeness grouped in the same row.

The numbers after some of the forms indicate roughly how many hits were generated for the form in searching Google. They give a rough idea of the relative commonness or rarity, although in an admittedly flawed and unscientific way. Forms that are listed in this color are rarities and exceptional forms, and should probably best be avoided.

Note that "ja" with negative "de gozaimasu" forms have an incongruence in level of formality and thus are not as acceptable, but they do occur occasionally in speech (and writing that emulates a spoken style).