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Longest Sentence Finder

Paste your text to see every sentence ranked by length. Find the ones that need breaking up and check your average sentence length against readability targets.

Input text
Sentences by length Longest first
Paste text to analyse sentences

Why Sentence Length Matters for Readability

Sentence length is one of the strongest predictors of readability. Long sentences force readers to hold more information in working memory before reaching the main point. They increase cognitive load, slow reading speed, and reduce comprehension — especially on screens and mobile devices where readers scan rather than read linearly.

Research on readability and plain language writing consistently finds that the ideal average sentence length for general audiences is 15–20 words. Academic writing averages 20–25 words. Sentences over 30 words are difficult for most readers. Sentences over 40 words are nearly always too complex and should be split.

Ideal Sentence Length by Audience

Audience / Context Target avg length Max comfortable length
General web content / blog14–18 words25 words
News articles / journalism15–20 words28 words
Academic / research papers20–25 words35 words
Legal / technical documents22–30 words50 words
Marketing copy / emails10–14 words20 words

How to Fix Long Sentences

When the tool identifies a sentence over 25–30 words, use one of these techniques:

  • Split at a conjunction — Break at "and", "but", "or", "because", "which", "that" to form two complete sentences.
  • Convert a clause to a new sentence — Relative clauses ("which has been shown to…") often stand alone as follow-up sentences.
  • Use a colon or dash — Replace a long clause with a colon or em dash for a shorter main clause plus a dependent elaboration.
  • Remove qualifiers — Long sentences often contain redundant hedges ("it could be argued that", "in many cases") that can be cut entirely.
  • Switch to active voice — Passive constructions are consistently longer than active equivalents.

Vary Sentence Length for Rhythm

Ideal writing is not uniformly short. A paragraph of only 8-word sentences reads as choppy and simplistic. The goal is a mix — shorter sentences for emphasis and rhythm, longer sentences to develop ideas — with the average staying under 20 words. After using this tool to find outliers above 30 words, run the readability checker to confirm the overall Flesch score improves after editing.

How the Longest Sentence Finder Works

Paste your text into the left panel. A stats bar appears above both panels showing four headline metrics: total sentence count, average words per sentence, the word count of the longest sentence, and the word count of the shortest sentence. The stats bar is hidden when the input is empty and reappears as soon as text is entered.

The right panel lists every sentence in your text sorted longest first — the sentence with the most words appears at the top. Each row shows the sentence's rank number (#1, #2, …), its word count, and a colour-coded badge: Long (red) for sentences of 30 words or more, and Short (blue) for sentences of 8 words or fewer. Sentences between those thresholds show no badge.

Use the Clear button in the input panel header to reset both panels and return to the empty state. For a more complete sentence analysis — including average words per sentence, sentence variety score, and an inline highlight view — use the sentence counter. Read our guide on ideal sentence length for readability.

Longest Sentence Finder FAQ

Common questions about finding and fixing long sentences.

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