Short Sentences: What Federal Plain Language Guidelines Recommend

Long sentences in a work email usually come from trying to be careful, not from trying to sound impressive. The problem is that a reader has to hold every clause in their head until the sentence finally ends, and by the third dependent clause, most readers have lost the thread. US federal plain language guidance, written for government agencies communicating with the public, gives concrete, testable rules for this problem that apply just as well to a business email.

The actual numbers behind "write short sentences"

The US Office of Personnel Management's plain language guidance states that sentence length should average 15 to 20 words, and that sentences which are simple, active, affirmative, and declarative hold a reader's interest better than long or complex ones. That is a specific target you can check yourself, not just a vague suggestion to "keep it short."

GSA's Digital.gov plain language guide series, which carries forward the official PlainLanguage.gov guidance, adds a rule about content, not just word count: express only one idea in each sentence. Its reasoning is direct: long, complicated sentences often mean you aren't sure what you want to say, and sentences loaded with dependent clauses and exceptions confuse the audience and bury the main point.

A before and after, counted word by word

The GSA guide includes a worked example of exactly this problem, rewriting a passive, clause-heavy passage into something shorter and more direct.

Before: "Once the candidate's goals are established, one or more potential employers are identified. A preliminary proposal for presentation to the employer is developed. The proposal is presented to an employer who agrees to negotiate an individualized job that meets the employment needs of the applicant and real business needs of the employer."

After: "Once we establish your goals, we identify one or more potential employers. We prepare a preliminary proposal to present to an employer who agrees to negotiate a job that meets both his and your employment needs."

Counting the words in both.

That comes to 52 words before and 36 words after, a 30.8 percent reduction. The rewrite did not lose any information. It switched passive constructions ("goals are established," "employers are identified," "is developed") to active ones ("we establish," "we identify," "we prepare"), and that alone removed a large share of the filler words needed to carry a passive sentence.

Why passive voice tends to run long

The pattern above is not a coincidence. A passive sentence needs a form of "to be" plus a past participle, and it often needs to describe who did the action in a separate phrase, if it says so at all. An active sentence puts the actor directly in the subject position, which tends to shorten the sentence and also makes it clear who is actually responsible for the action, something a reader has to guess at in a passive construction.

For a work email, this translates directly: "The report was reviewed and some changes were recommended" leaves the reader asking who reviewed it and who is recommending what. "I reviewed the report and recommend three changes" answers both questions in fewer words.

Applying this to an email you are about to send

A practical way to use the 15 to 20 word guideline without obsessively counting every sentence:

1. Draft the email the way it first comes to mind.
2. Read each sentence and ask whether it contains more than one idea. If it does, split it at the natural break (often where you used "and," "which," or a comma followed by a new clause).
3. Check for a passive construction ("is being handled," "was sent," "will be reviewed") and rewrite it with a clear subject doing the action.
4. If a sentence still feels long when read aloud in one breath, it is a candidate for splitting.

This is also consistent with the paragraph-level guidance from the same GSA guide series: paragraphs should generally run no more than 150 words across three to eight sentences, and should cover only one topic, which keeps a reader from losing track of the point partway through.

Key takeaways

• US federal plain language guidance recommends an average sentence length of 15 to 20 words.
• One idea per sentence is a separate, content-level rule, not just a word count target.
• In the GSA's own before and after example, rewriting passive sentences into active ones cut the word count by 30.8 percent without losing information.
• Passive voice tends to add words because it needs "to be" plus a past participle and often omits who did the action.
• When editing an email, split sentences with more than one idea and rewrite passive constructions so a clear subject performs the action.