What is a good Flesch Reading Ease score?

Scores range from 0 to 100, where higher is easier. 60-70 is plain English suitable for a general audience, 30-50 is fairly difficult and college-level, and below 30 is very hard. Most consumer-facing copy should aim for 60 or above.

How is grade level computed?

Flesch-Kincaid Grade Level combines average sentence length and average syllables per word into a US school grade number. A score of 8 means an average eighth-grader can read it. Gunning Fog and SMOG use similar inputs but weight complex multi-syllable words more heavily.

Why does LLM output tend to score as complex?

Language models often default to long sentences, nominalizations, and formal vocabulary. That pushes grade level up. Asking the model to write at a specific reading level, or running its output through a scorer like this, helps catch and correct that drift.

How accurate is the syllable count?

Syllables are estimated with a vowel-group heuristic that handles silent e and common patterns. It is accurate enough for readability scoring across a paragraph, though individual unusual words may be off by one. The indices are robust to small per-word errors.

AI Output Readability Scorer

Make sure your AI output actually reads at the right level

Language models frequently default to long, formal, multi-syllable prose that scores several grades above what a general audience comfortably reads. This tool runs your LLM output through four established readability formulas — Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, and SMOG — and tells you whether it matches your target audience, then flags the sentences dragging the score up.

How it works

Paste the text and the tool tokenizes it into sentences and words, estimates syllables with a vowel-group heuristic, and counts complex words (three or more syllables). From those counts it computes all four indices. Flesch Reading Ease returns a 0-100 score where higher is easier; the other three return a US grade level. You pick a target grade, and the tool shows how far each index is from it. Finally it ranks individual sentences by length and difficulty so you know exactly which ones to simplify.

Tips and example

For consumer-facing copy, aim for a Flesch Reading Ease of 60+ and a grade level around 7-9. If your model output lands at grade 13, the fastest fix is to add a constraint to the prompt — “write at a 7th-grade reading level, short sentences, plain words” — and re-score. Watch the flagged sentences: a single 40-word sentence stuffed with jargon can pull the whole document up two grades, so breaking it into two or three plain sentences often does most of the work. The syllable estimate is heuristic but the indices are robust across a paragraph.