Readability Score Checker

Flesch Reading Ease

The best-known readability measure, and the only one here that produces a 0–100 score rather than a grade. It weighs average sentence length and average syllables per word: shorter sentences and shorter words push the score up.

The three grade-level scores

Flesch-Kincaid, SMOG and ARI all report an approximate US school grade, but they measure difficulty differently, which is why they are shown together.

• Flesch-Kincaid Grade Level uses sentence length and syllables per word. It is the most widely cited and is what most style guides mean by "grade level".
• SMOG Index counts words of three or more syllables. It is the standard in healthcare, where it is used to check that patient information is genuinely accessible. It is defined on a 30-sentence sample and this tool reports 0 for shorter text rather than extrapolating from too little data.
• ARI uses characters per word instead of syllables. Because character counting is unambiguous where syllable counting is estimated, ARI is the most mechanically reliable of the three — though it treats a long word as hard even when it is common.

What the scores cannot tell you

Every formula here works from two inputs: how long your sentences are and how long your words are. That is all. It is a genuinely useful proxy, and it is also blind to most of what makes writing clear.

A score cannot tell whether your text is accurate, well organised, in a sensible order, or free of jargon. It rewards short words, so it will happily score an undefined acronym as easy and a clear everyday word like "understand" as harder. It has no view on whether you defined your terms or buried the answer in the last paragraph.

You can also game it trivially — chop every sentence in half and the scores improve while the writing gets worse. Treat these numbers as a signal that something may need attention, not as a target.

What to aim for

The right level depends entirely on who is reading. There is no universally correct score.

How to actually improve readability

The changes that move the scores are also the changes that genuinely help a reader.

• Split long sentences. One idea per sentence. Average words per sentence is shown on this page — aim for 15–20 for general audiences.
• Prefer the shorter word when it means the same thing: "use" over "utilise", "help" over "facilitate".
• Cut the throat-clearing. "It is important to note that" is five words before the sentence starts.
• Use active voice. "We reviewed the data" is shorter and clearer than "the data was reviewed by us".
• Define jargon on first use, or replace it. Formulas score an undefined acronym as easy; readers do not.
• Break up walls of text with subheadings and lists. Formulas ignore layout entirely; readers do not.