Private Writing AssistantHow long should a sentence be?
Long enough for one idea, and no longer. There is no ideal word count, because languages build sentences differently, but a sentence that carries two or three ideas is almost always easier to read as two or three sentences.
Why word counts don't settle it
You'll find rules like “never more than 20 words”. They're a useful alarm, but a poor rule. German and Finnish pack meaning into long compound words, Chinese and Japanese don't put spaces between words at all, and a precise sentence in a contract has to be as long as the condition it states.
A better test works in every language: how many ideas does the reader have to hold before the full stop?
One idea per sentence
A sentence is a unit of attention. The reader keeps it in mind until the full stop, then lets go. Put three ideas in one sentence and the reader has to hold all three, work out which one matters, and remember how they connect, all at once.
The new booking system, which IT rolled out on Monday after two weeks of testing with the sales team, replaces the old spreadsheet, so please stop using the spreadsheet from today, and if anything looks wrong, contact the help desk rather than editing entries by hand.
From today, please book in the new system instead of the old spreadsheet. If anything looks wrong, contact the help desk rather than editing entries by hand. IT rolled the system out on Monday after two weeks of testing with the sales team.
The first version isn't wrong. It's four messages in one sentence, with the instruction buried in the middle. The second puts the instruction first, the exception second and the background last, where readers who don't need it can stop.
Where to split
Split where the idea changes. Good places are the words that start a new thought, such as “and”, “but”, “so” and “which”, and the asides you set off with commas or brackets. After splitting, move the sentence that matters most to the front.
Keep parts together when they depend on each other. A condition and its result belong in one sentence: “If the payment fails, the order is cancelled.” Split that, and the second sentence means nothing on its own.
Mix the lengths
A page of only short sentences sounds clipped, like a list read aloud. Vary them: a short sentence for the point, a longer one for the reasoning, a short one to land it. If three sentences in a row have the same length and the same shape, the reader starts to skim.
Reading aloud is the quickest check. A sentence you can't say in one breath is usually carrying more than one idea.
When long sentences are right
Some long sentences earn their length: a list of items, a precise legal or technical condition, a quotation. Readers of some languages also expect longer sentences in formal writing than in English. The goal was never short. It's easy to follow.
Get a second version to compare
When a sentence has grown out of control, it helps to see it rewritten. In Private Writing Assistant, select it, press Rewrite and choose Simpler or Shorter. You get a new version with the changes highlighted, in the same language. Keep it, try again, or take one idea from it and write the rest yourself.
Private Writing Assistant checks and rewrites text in 101 languages with Chrome Built-in AI, on your own computer. The FAQ shows where it works.
