# Readability Calculator > Readability calculator: score any text with Flesch Kincaid grade level and reading ease to check comprehension. Free, runs in your browser, no signup. - **Canonical URL:** https://boringtoolskit.com/readability/ - **Category:** Text & Developer Tools - **Evidence level:** authored-methodology - **Reviewed:** October 2026 - **Last verified:** 2026-10-12 - **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request. ## How it works Flesch Reading Ease = 206.835 - 1.015 x (words per sentence) - 84.6 x (syllables per word); Flesch-Kincaid Grade = 0.39 x (words per sentence) + 11.8 x (syllables per word) - 15.59. ## Worked example 16 plain words in 3 sentences with 16 syllables: 206.835 - 1.015 x (16/3) - 84.6 x 1.0 = 116.8, very easy. One dense 11-word industrial sentence at 1.8 syllables per word scores 41.9. ## Assumptions - Syllable counts come from a vowel-group heuristic with one silent-e removal per word, not a dictionary, so unusual spellings can differ by a syllable from human judgment. - Sentences are split on . ! ? and every nonempty fragment counts: abbreviations like 'Mr.' split a sentence and raise the words-per-sentence figure slightly. - Flesch Reading Ease measures only structural difficulty, sentence length and word length, not quality or clarity of the underlying ideas. - Published benchmark rows describe the historical reference examples of the scale (Reader's Digest, Time, Harvard Law Review), not fresh measurements of current issues. ## Common questions ### What is a readability calculator and how does it work? A readability calculator counts words, sentences, and syllables in your text and returns two scores: Flesch Reading Ease (0 to 100 in practice, higher is easier) and the Flesch-Kincaid Grade Level (roughly the US school grade needed to read the text). ### Do I need to create an account or sign up to use this readability calculator? No, this readability calculator is a no-signup, browser-based tool that processes your text locally on your device without storing any data. ### Why should I use a readability calculator for my writing? You should use a readability calculator to ensure your content is accessible to your target audience by identifying overly complex sentences and vocabulary. ### What is a good Flesch Reading Ease score? For a general adult audience, aim for 60 to 70, the band an average sixth-grade student's writing occupies. Scores below 50 read as fairly difficult, and below 30 is very difficult, graduate-level material. ### Why is my score negative, or above 100? The formula has no bounds. A one-syllable word in a short sentence scores above 116, and text packed with polysyllabic words can go negative. Both are expected for extreme inputs, not errors. ### How accurate is the syllable counting? It is a heuristic: vowel groups per word with one silent-e removal per word, and every word contributes at least one syllable. Dictionary-perfect counting can differ by a syllable on unusual spellings, but the score's ranking behavior is stable. ## Related tools - /word-counter/ - /keyword-density-calculator/ - /reading-speed-calculator/ ## Sources - [Plain language guide series (US federal plain-language writing standards)](https://digital.gov/guides/plain-language/) - [Flesch-Kincaid readability tests (formula constants and published score anchors)](https://en.wikipedia.org/wiki/Flesch%E2%80%93Kincaid_readability_tests) - [Calculation methodology](/methodology/) - [Quality evidence and verification standard](/quality-evidence/) --- *Local planning estimate. Verify current terms, rates, and policies before acting.*