Readability checker
Flesch Reading Ease and grade level, with sentence length and passive voice flagged.
How it works
Scores text with the Flesch Reading Ease and Flesch–Kincaid Grade Level formulas, and highlights the sentences that pull the score down.
Both formulas count only syllables per word and words per sentence. That is their strength and their limit: they are objective and reproducible, and they measure nothing about whether the writing is clear. A passage of short familiar words in short sentences that says nothing scores well; a precise technical sentence scores badly. Treat a poor score as a prompt to look, not as a verdict.
Reading Ease runs from 0 to 100, higher being easier. Roughly: 90–100 is very easy, 60–70 is plain English and the level most general writing aims at, 30–50 is difficult, and below 30 is very difficult. Grade Level converts the same measurement into US school years.
The tool also counts filler words, flags sentences over about 25 words, and estimates passive voice by looking for a form of "to be" followed by a past participle — which is a heuristic and will produce some false positives.
This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.
Common questions
- What is a good Flesch Reading Ease score?
- Around 60–70 is plain English and what most general writing aims for. Below 30 is very difficult. Government and health writing often targets 60 or above.
- Does a good readability score mean good writing?
- No. The formulas count syllables and sentence length and nothing else. Simple words arranged meaninglessly score well; a precise technical sentence scores badly.
- Is passive voice bad?
- Not inherently. It is the right choice when the actor is unknown or irrelevant. It is worth flagging because it is overused, not because it is an error.
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- Regex tester Test a regular expression against sample text, with matches and capture groups shown.
- Case converter Convert text between upper, lower, title, sentence, camel, snake, kebab and other cases.
- Remove empty lines Delete blank lines from a block of text, optionally collapsing runs to one.
- Find and replace Replace every occurrence of a string in pasted text, with optional regex.
Sources
- Derivation of New Readability Formulas for Navy Enlisted Personnel — Kincaid et al., US Navy Research Branch Report 8-75, 1975