Most readers feel comfortable reading paragraphs that range between one hundred and two hundred words. Shorter paragraphs force too much starting and stopping, and longer ones strain the reader’s attention span. There are exceptions to this guideline, however.

Paragraphs longer than two hundred words frequently appear in scholarly writing, where they suggest seriousness and depth. Paragraphs shorter than one hundred words occur in newspapers because of narrow columns; in informal essays to quicken the pace; in business letters, where readers routinely skim for main ideas; and in e-mail and on Web sites for ease of reading on the computer screen.

In an essay, the first and last paragraphs will ordinarily be the introduction and the conclusion. These special-purpose paragraphs are likely to be shorter than the paragraphs in the body of the essay.

Typically, the body paragraphs will follow the essay’s outline: one paragraph per point in short essays, a group of paragraphs per point in longer ones.

EXCEPTION: Some ideas require more development than others, so it is best to be flexible. If an idea stretches to a length unreasonable for a paragraph, you should divide the paragraph, even if you have presented comparable points in the essay in single paragraphs.

Beware of using too many short, choppy paragraphs. Readers want to see how your ideas connect, and they become irritated when you break their momentum by forcing them to pause every few sentences.