The number of paragraphs in an essay is determined by the type of essay that you write. A general compare and contrast essay can have four paragraphs at minimum. These four paragraphs will consist of an introductory paragraph, two body paragraphs and a concluding paragraph. All essays will have an introductory and concluding paragraph. Therefore, the total number of paragraphs in an essay will be determined by the number of body paragraphs that the essay may require.
An essay typically has five paragraphs. The first paragraph up to the third paragraph would be the body. The last paragraph would have the conclusion of the essay. For a sample of what an essay looks like and what to include in a concluding paragraph go to this site: http://grammar.ccc.commnet.edu/grammar/five_par.htm