Sentence Counter
Count sentences and calculate average sentence length in any text. Enter values for instant results with step-by-step formulas.
Formula
Flesch Reading Ease = 206.835 - 1.015(words/sentences) - 84.6(syllables/words)
Sentences are counted by terminal punctuation marks. The Flesch Reading Ease score combines average sentence length and syllable density to estimate readability on a 0-100 scale. The Flesch-Kincaid Grade Level converts this to a US school grade.
Frequently Asked Questions
How does the sentence counter identify sentences?
This sentence counter identifies sentences by detecting sentence-ending punctuation marks including periods, exclamation marks, and question marks. The algorithm handles common edge cases such as abbreviations and decimal numbers to some extent, though complex abbreviations like U.S.A. or Mr. may occasionally affect the count. Each sequence of text terminated by one or more sentence-ending punctuation marks is counted as one sentence. If the text ends without terminal punctuation, the remaining text is counted as an additional sentence. For the most accurate count, ensure your text uses standard punctuation conventions. The counter works with English text and may produce different results with languages that use different punctuation rules.
What is a good average sentence length for readability?
Research on readability consistently shows that shorter sentences are easier to understand. The average sentence length in published English prose is approximately 15 to 20 words. For web content and journalism, experts recommend keeping the average between 14 and 18 words per sentence. Academic and technical writing typically averages 20 to 30 words per sentence. Legal documents often exceed 30 words per sentence, contributing to their reputation for being difficult to read. However, variation is important. A mix of short punchy sentences and longer more complex ones creates rhythm and keeps readers engaged. Consistently uniform sentence length makes writing feel monotonous regardless of whether sentences are all short or all long.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
Is Sentence Counter free to use?
Yes, completely free with no sign-up required. All calculators on NovaCalculator are free to use without registration, subscription, or payment.
How do I interpret the result?
Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.
What formula does Sentence Counter use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.