Which formulas are used?

Flesch Reading Ease, Flesch–Kincaid Grade, Gunning Fog, SMOG, Coleman–Liau and Automated Readability Index, plus a consensus grade — all computed from your text in the browser.

What grade level should I aim for?

About grade 8 for general-audience writing, grade 12 for professional documents, and higher only for technical or academic work. Pick the audience and the page tells you whether you are over.

Why are some sentences underlined?

Sentences over 20 words are amber and over 30 are red — they are where readers most often lose the thread. Blue marks passive constructions.

Readability Checker — Flesch, Grade Level & Hard Sentences

Score reading ease and grade level with six classic formulas, pick your audience, and see the specific long sentences making the text hard — underlined in place, computed in your browser.