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About this tool
Scores your text with Flesch Reading Ease, then builds a rewrite prompt targeting a chosen tone and reading level.
This builder scores your text with the Flesch Reading Ease formula — 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words) — and the Flesch–Kincaid grade level, then writes the rewrite prompt that moves it to the tone and readability band you choose. The prompt carries the measured numbers, the size of the gap in Flesch points, and an explicit list of what must not change: facts, quotations, structure, terminology or length. It is for writers, support teams and anyone turning dense copy into something a specific reader can actually follow.
Open AI Tone Rewrite Prompt Builder on AltFTool — it loads instantly in your browser.
Provide your input — an image, text, or data.
Let the tool analyze or generate the result.
Review, refine, and reuse the output wherever you need it.
Both Flesch formulas run on your text before the prompt is written, so the model is told exactly how far it has to move.
Tick the things the rewrite must not touch — facts, quotes, Markdown, headings — and they become explicit prompt rules.
Each tone is a concrete instruction about voice, hedging and sentence shape rather than a one-word label.
For public-facing writing, aim for 60–70, which the Flesch scale labels Plain English at roughly an 8th to 9th grade reading level. Consumer copy often targets 70–80, while academic and legal text commonly falls below 50.
The formula is 206.835 − 1.015 × (total words ÷ total sentences) − 84.6 × (total syllables ÷ total words). Only sentence length and syllable count feed it, which is why a short sentence of nonsense can still score highly.
Reading Ease is a 0–100 scale where higher means easier; Flesch–Kincaid converts the same two inputs into a US school grade using 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. A grade level of 8 means an average eighth-grader should follow it.
Because nothing in a plain 'make this friendlier' instruction forbids it. Naming the constraints explicitly — do not add, remove or alter any fact, name, date or figure; reproduce quotations verbatim — is what stops the drift, and this tool writes those rules into the prompt for you.