Readability Score

Readability formulas turn three counts — sentences, words and syllables — into a school grade. They are blunt instruments, and they are still the fastest way to find out that a paragraph you thought was clear reads like a legal notice. Six are calculated at once, because they disagree in useful ways. As a reading level checker it gives you all of them rather than picking one and hoping. Flesch Reading Ease gives a 0 to 100 score where higher is easier. Flesch-Kincaid, Gunning fog, SMOG, Coleman-Liau and the Automated Readability Index all answer in US school grades. When they agree, the text is genuinely easy or genuinely hard. When they split, one long sentence or one long word is usually doing the damage — so the longest sentence is named, because breaking it in half is nearly always the fix. This is an accessibility tool as much as a writing one. WCAG success criterion 3.1.5 asks that text needing reading ability beyond lower secondary education comes with a simpler alternative, which is a readability threshold written into an accessibility standard. One honest limitation: syllable counting in English is an approximation. Spelling and sound have no reliable relationship — "queue" is one syllable and looks like three — so these scores are useful across a paragraph and should not be trusted about a single sentence. Everything runs in your browser.