Online Sentence Counter
Count sentences, words, characters, paragraphs, and average sentence length in real time. Paste your text and get instant, detailed analysis — free, no signup required.
How Does the Sentence Counter Work?
The sentence counter analyses your text and detects sentence boundaries using punctuation marks — specifically periods (.), question marks (?), and exclamation marks (!). It handles common edge cases including abbreviations (e.g., Dr., Mr., i.e., etc.), decimal numbers (3.14), ellipses (...), and multiple consecutive punctuation marks (!!! or ???). Each detected sentence boundary is counted once, giving you an accurate sentence count that closely matches what a human reader would count.
What Is the Flesch-Kincaid Readability Score?
The Flesch-Kincaid Reading Ease formula calculates how easy a piece of text is to read on a scale of 0 to 100. A score of 90–100 means the text is very easy to read (e.g. children's books). A score of 60–70 is considered standard — suitable for the average adult reader (e.g. newspapers). A score below 30 is very difficult and typically found in academic or legal texts. The formula is based on average sentence length and average number of syllables per word — shorter sentences and simpler words produce higher (easier) scores.
What Is Average Sentence Length and Why Does It Matter?
Average sentence length is the number of words divided by the number of sentences. Research consistently shows that sentences between 15 and 20 words are the most readable for general audiences. Sentences shorter than 10 words can feel choppy and disconnected, while sentences longer than 30 words become difficult to follow, especially online where readers tend to scan rather than read in full. Varying sentence length — mixing short punchy sentences with occasional longer ones — creates a natural rhythm that holds the reader's attention.
How Are Syllables Counted?
Syllable counting uses a phonetic estimation algorithm that counts vowel groups within each word — groups of consecutive vowel letters (a, e, i, o, u) typically correspond to one syllable. Silent vowels at the end of words are subtracted. This approach is accurate for most common English words, though highly irregular words or technical terminology may occasionally be miscounted. The syllable count is used as an input to the Flesch-Kincaid readability calculation.
What Is the Difference Between Sentences and Paragraphs?
A sentence is a grammatical unit that expresses a complete thought and ends with a punctuation mark (period, question mark, or exclamation mark). A paragraph is a group of related sentences separated from other groups by a blank line or line break. This tool counts paragraphs by detecting double line breaks (or sequences of newlines) that separate blocks of text. For academic writing, a typical paragraph contains 3–8 sentences. For online content, shorter paragraphs of 2–4 sentences are recommended for better readability on mobile screens.
After counting sentences, run an AI grammar check to fix errors in spelling, punctuation, and grammar — free, instant, no signup.
Try It Free →Aim for an Avg Words/Sent of 15–20 for blog content and 10–15 for email copy. If your average exceeds 25, try breaking long sentences into two shorter ones to improve readability.