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Sentence counter online

A sentence here is a fragment of text between periods, exclamation and question marks. For text without terminal punctuation (lists, slide captions) there's a separate option to also treat a line break as a sentence boundary.

Your data never leaves this device

Result

Sentences
Average words per sentence
Words in the longest sentence

This page has no server side at all. The table you paste is parsed by JavaScript inside your own browser, the chart is drawn on a canvas element on your machine, and the export file is assembled locally. Nothing is uploaded, stored or written to any log. You can disconnect from the network after the page has loaded and everything will still work — which is the simplest way to verify the claim yourself.

Facts and limits of this method

Sentence A text fragment up to a period, exclamation or question mark
Boundary One or more marks in a row ("?!", "...") count as a single boundary
With the line-break option Every new line is also treated as the end of a sentence, even without a period
Average length Total words across all sentences ÷ number of sentences

When it misleads you

How it is calculated

Without the line-break option, the text is split into sentences on periods, exclamation and question marks in a row (e.g. "?!" or "…" count as one boundary).

With the option on, a line break is added to those boundaries too — this turns the tool into a "list item" counter rather than a strict "sentence with terminal punctuation" counter.

For each sentence found, the word count (runs of non-whitespace characters) is computed, from which the average length and the longest sentence's length are derived.

Empty fragments (for example, between two consecutive periods) are discarded and don't increase the count.

Questions and answers

Why is the sentence count higher than what I counted by hand?

The text probably contains abbreviations or decimal numbers with a period — the counter treats those periods as sentence endings. This is a limitation of the simple heuristic, which looks for punctuation marks rather than understanding meaning.

How do I count a list without terminal punctuation on each line?

Turn on "also treat line breaks as sentence boundaries" — then each list line is counted as a separate "sentence," even without an ending mark.

What counts as the longest sentence?

The one with the most words — not the most characters. A word here is a run of non-whitespace characters.

Is my text sent anywhere?

No, the whole count runs in your browser.

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