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Sentence Counter – Count Sentences and Average Length

Count sentences, estimate reading time, and review average sentence length for any text block.

If this tool isn’t working as expected, please take a screenshot of the error and report the problem here so we can investigate and improve it.

About this tool

Sentence count and average sentence length are useful readability signals - a lower average generally reads easier, while a long "longest sentence" can flag copy that needs tightening. Reading time uses the same 200-words-per-minute estimate as this site's Word Counter, so the two tools agree on timing.

A period only ends a sentence when it is followed by a space or the end of the text, and not after titles and abbreviations such as Mr., Dr., e.g., and i.e., so "Dr. Smith went home." is one sentence and "The price is 3.5 dollars." is one sentence.

The rules are heuristics, so unusual abbreviations can still be miscounted.

A sentence counter that splits pasted text at periods, question marks, and exclamation points to report a sentence count, average words per sentence, an estimated reading time, and a preview of the longest sentence. It uses rule-based detection - not a language model - that recognizes decimals, domain names, common abbreviations, initials, and list numbers instead of treating every period as the end of a sentence.

How to Use Sentence Counter

Paste Text

Add the copy, article, or message you want to analyze.

Count Sentences

The tool detects sentence breaks and totals the result instantly.

Check Reading Time

Review estimated reading time and average sentence length.

Inspect Long Sentences

Use the longest-sentence preview to spot lines that may need shortening.

Common Workflows

Paste Your Text

Add the article, essay, or message you want to analyze into the input box.

Review the Stats

Check sentence count, average words per sentence, and estimated reading time, updated instantly as you type.

Inspect the Longest Sentence

Read the longest-sentence preview to spot a line that may need to be shortened.

Reset and Try Another Draft

Use the Reset button to clear the text and start again with a new draft.

Best For

  • Reports sentence count, average words per sentence, reading time, and a longest-sentence preview - all four stats calculated instantly as you type.
  • Decimal numbers (3.14), domain names (example.com), versions (v2.1.3), titles and abbreviations (Dr., Mr., e.g., etc.), initials (J. K. Rowling), and numbered-list markers (1.) are not counted as sentence breaks.
  • Runs entirely in your browser - the text you paste is not uploaded, and there is no sign-up.

Examples

Abbreviations do not split sentences

Input

"Dr. Smith arrived. He was late."

Result

2 sentences: "Dr. Smith arrived." and "He was late."

The period after "Dr" is recognized as part of a title, so only the periods that really end a sentence are counted.

Decimal numbers and domain names stay inside their sentence

Input

"This is version 2.5. Visit example.com today."

Result

2 sentences: "This is version 2.5." and "Visit example.com today."

A period inside 2.5 or example.com is not followed by a space, so it is not a sentence end; only the periods that are followed by a space or the end of the text can end a sentence.

Use Cases

Checking sentence variety in a draft

Paste an essay or blog post to see the sentence count and average sentence length at a glance.

Spotting an overly long sentence

Use the longest-sentence preview to find a run-on sentence worth splitting into two.

Estimating reading time for an article

Reading time uses the same 200 words-per-minute formula as this site's Word Counter, so the two agree on timing.

Comparing the average sentence length of two drafts

Paste each draft in turn and compare the Avg Words / Sentence figure to judge which reads more simply.

Common Mistakes

Problem

Assuming every abbreviation is recognized

Solution

Common titles and abbreviations (Mr., Dr., Prof., e.g., i.e., etc., Inc., a.m., p.m.) are handled, but an unusual abbreviation followed by a capitalized word can still be counted as a sentence end.

Problem

Expecting a heading without punctuation to count separately

Solution

A sentence is only ended by . ! or ?. A title or list item without end punctuation is joined to the text that follows it.

Problem

Expecting a word count or character count here

Solution

This tool does not display a standalone word, character, or paragraph count - use the Word Counter for those totals.

Problem

Expecting a speaking-time estimate

Solution

Only reading time is calculated. There is no speaking-time or presentation-duration feature.

Tips & Best Practices

Use Word Counter for overall text totals

If you need word count, character count, or paragraph count, use the Word Counter - this tool focuses on sentence-level structure instead.

End headings and list items with punctuation if you want them counted

Only . ! and ? end a sentence, so unpunctuated lines are joined to the next sentence.

Use the longest-sentence preview to find run-ons

It's measured by character length, not word count, so use it alongside the average-length figure to judge readability.

Stick to English-style punctuation for accurate counts

Sentence detection only recognizes the ASCII period, question mark, exclamation point, and the ellipsis character - text using other scripts' sentence-ending punctuation will undercount.

Limitations

Rule-based, not language-aware

A period ends a sentence when it is followed by a space or the end of the text, except after a built-in list of titles and abbreviations, initials, and list numbers. Unusual abbreviations can still be miscounted.

Needs end punctuation

Only . ! ? and … end a sentence, so headings and list items without punctuation are joined to the following text.

No word, character, or paragraph count

Only sentence count, average words per sentence, reading time, and longest sentence are calculated - word counts are used internally for the average but never displayed on their own.

No speaking-time estimate

Only reading time (200 wpm) is calculated. There is no separate speaking or presentation-duration figure.

Longest sentence is measured by character length, not word count

The "longest sentence" preview picks the sentence with the most characters, which is not always the sentence with the most words.

Only recognizes ASCII sentence-ending punctuation

Non-Latin sentence terminators, such as the Urdu/Arabic full stop "۔", are not recognized as sentence boundaries, which can severely undercount sentences in text that doesn't use the ASCII period.

Comparisons

This Tool vs. Word Counter

Both analyze pasted text, but they report different things.

Sentence CounterWord Counter
FocusSentence-level structure - count, average length, longest sentenceOverall text totals - words, characters, and reading time
Word count displayedNo - words are only used internally to calculate the averageYes - a headline stat
Reading time formula200 words per minute200 words per minute (same formula)
Speaking timeNot calculatedNot calculated

FAQs

The most common question is how sentences are actually detected, since splitting on every period would miscount text with abbreviations or decimal numbers. The FAQ below explains the splitting rules, what "longest sentence" measures, and how reading time is calculated.

How does this tool actually detect sentences?

A period, question mark, exclamation point, or ellipsis ends a sentence when it is followed by a space or the end of the text. A period does not end a sentence inside a decimal number or domain name (3.14, example.com), after a title or abbreviation such as Dr., Mr., e.g., or i.e., after an initial (J. K. Rowling), or after a list number at the start of a line. Abbreviations such as etc. or Inc. end a sentence only when the next word is capitalized. It is rule-based, not a language model, so unusual abbreviations can still be miscounted.

Does "Dr. Smith arrived." count as one sentence or two?

One. The period after "Dr" is recognized as part of a title, so only the final period ends the sentence.

Does a decimal number like "3.14" split into two sentences?

No. A period that is not followed by a space - as in 3.14 or example.com - is not treated as a sentence end.

Does it estimate speaking time for presentations?

No. Only reading time is calculated, using a fixed 200 words-per-minute estimate. There's no separate speaking-time or presentation-duration figure.

Is the "longest sentence" the one with the most words?

No. It's the sentence with the most characters, which isn't always the sentence with the most words - a sentence with a few long words can be picked over one with more, shorter words.

Does it show a word count or character count?

No. Word counts are used internally to calculate the average words-per-sentence figure, but they aren't displayed on their own - use the Word Counter for standalone word and character totals.

Does it work on non-English text?

It works on any text using the ASCII period, question mark, or exclamation point as sentence enders. Scripts that use different sentence-ending punctuation, such as the Urdu/Arabic full stop "۔", aren't recognized, which can severely undercount sentences.

Is my text uploaded anywhere?

No. CoditTools's sentence counter runs entirely in your browser - your text is never sent to any server.

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