How does the tool count clauses?

It starts each sentence at one and adds one for every coordinating conjunction, subordinating conjunction, relative pronoun, semicolon and colon. It is a documented estimate rather than a grammatical parse, and the page lists every marker it looks for.

Why are commas not treated as clause boundaries?

Because a list of three items separated by commas is a single clause, and counting commas would make every list look like four clauses. Commas are shown per sentence so you can see them, but they never raise the estimate.

What words-per-clause figure is comfortable?

There is no universal threshold, but a figure above roughly 20 words per clause usually means a sentence is carrying more than one idea. Below about 8 it tends to read as choppy. The average and the worst offenders are both reported so you can judge in context.

Does a long sentence always mean a complex one?

No. A 35-word sentence built from one clause with long noun phrases is not multi-clausal, and the tool will not flag it as such. Length and clause load are separate columns precisely so you can tell the two cases apart.

Can the clause estimate be wrong?

Yes. Without a parser it cannot distinguish a restrictive clause from an appositive, and it does not understand ellipsis or unusual punctuation. Use it to shortlist sentences for a second look rather than as a grade.

Sentence Complexity Analyzer

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Complexity at a glance

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The Sentence Complexity Analyzer estimates how many clauses each sentence carries, ranks the heaviest ones and states exactly how the clause count is derived, so you can see which sentences to split before a reader gives up on them.

What is Sentence Complexity Analyzer?

Most sentences that read badly are not badly chosen words; they carry too many ideas at once. The Sentence Complexity Analyzer estimates the clause load of every sentence in your text, then ranks the sentences that carry the most, so the rewrite can start where it matters.

The clause count is an estimate with the method published on the page, because a browser tool does not have a parser and pretending otherwise would be dishonest. A sentence starts at one clause. It gains one for each coordinating conjunction, each subordinating conjunction, each relative pronoun, and each semicolon or colon. Commas are displayed but never counted. That last decision is deliberate: a list of three items separated by commas is one clause, and a tool that treated every comma as a boundary would make ordinary grocery lists look unreadable.

Alongside the clause estimate, each sentence is measured for words, characters, commas, words of three or more syllables and words of seven or more letters. Those figures are exact — they come from the same Unicode tokenizer the whole domain uses — so even when you disagree with the clause estimate you are still looking at true counts. Words per clause is the estimate divided into the sentence length, and it is the single most useful number here: a sentence of 40 words in two clauses is dense, while a sentence of 40 words in six clauses is merely busy.

The summary reports the average clause estimate, the average words per clause, the share of sentences that are single-clause, and the share carrying three or more clause markers. Below that sit two ranked tables: the sentences with the most clauses, and the longest sentences with their comma and long-word counts. Those tables are where an editing pass begins. A sentence that is long and multi-clausal is the usual culprit; a long sentence with one clause is often fine and simply needs no change.

The estimate has a known blind spot and the page names it. Without a parse it cannot tell a restrictive relative clause from an appositive, so a sentence with several that or which phrases scores higher than its meaning warrants, and a sentence built from long noun phrases scores lower than it reads. Treat the ranking as a list of sentences worth reading again, not as a verdict on each one.

Complexity is not a fault by itself. Academic and legal writing often needs subordination to keep a qualification next to what it qualifies, and splitting such a sentence can change its meaning. The tool is most useful on prose that intends to be clear: marketing copy, documentation, essays, instructions. There, a high words-per-clause figure usually identifies a sentence that has quietly acquired three separate points and would be clearer as two or three.

One last use is diagnostic rather than corrective. If a readability score comes out high while the vocabulary is plainly simple, the cause is usually complex sentences rather than difficult words, and the ranked tables here name them without your having to guess. A single heavily subordinated sentence can raise a whole paragraph's grade, and finding it is often the entire fix.

How to use Sentence Complexity Analyzer

Paste the text you want to examine; every sentence is measured as you type.
Read the average clauses per sentence and the average words per clause in the summary panel.
Open the table of sentences carrying the most clauses and read the top few in full.
Check the longest-sentences table for sentences that are long but single-clause, which often need no change.
Split the genuinely overloaded sentences, paste the revision back, and watch the averages fall.

When to use Sentence Complexity Analyzer vs related tools

Use the complexity analyzer when individual sentences feel heavy and you need to find which ones. When the issue is the overall distribution rather than any single sentence — every sentence the same length, or a monotonous stretch — the Sentence Variety Checker measures the spread instead.

If the sentences are fine and the difficulty is in the vocabulary, the Readability Grade Scorer will show that in the syllable-based scores, and the Flesch-Kincaid Score Calculator breaks the same reading into its two Flesch formulas.

Privacy & Security

This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.