Analyze your content with 4 readability formulas — Flesch-Kincaid, Gunning Fog, SMOG, and Dale-Chall. See sentence-level highlights, grade level, and actionable tips.
The most widely used readability formula. Scores range from 0–100. Higher = easier. Scores above 60 are considered readable for general audiences.
206.835 − (1.015 × words/sentences) − (84.6 × syllables/words)
60–70: Standard. 70–80: Fairly easy. 80–90: Easy. Below 30: Very difficult.
Estimates years of formal education needed to understand the text on first reading. A score of 12 corresponds to US high school level. Below 8 is ideal for general web content.
0.4 × ((words/sentences) + 100 × (complex words/words))
Complex words are those with 3+ syllables, excluding proper nouns and compound words.
Simple Measure of Gobbledygook — designed for health communication. More accurate than FK for medical and technical content. Requires at least 30 sentences for reliable results.
3 + √(polysyllable count × (30 / sentences))
Polysyllables are words with 3+ syllables. Output is a US grade level.
Based on a list of ~3,000 familiar words known to 4th graders. Words not on the list are "difficult." Very accurate for predicting comprehension difficulty.
0.1579 × (difficult words/words × 100) + 0.0496 × (words/sentences)
If difficult words exceed 5%, add 3.6365 to the raw score.
RankAl SEO shows a live readability score in your Gutenberg editor as you write — no copy-pasting needed.
Google's quality guidelines prioritize content written for humans, not algorithms. Clear, well-structured writing reduces bounce rates and increases dwell time — both positive ranking signals.
A general blog should target grade 6–8 (Flesch-Kincaid 60–70). Technical docs can go higher. Healthcare content should stay below grade 8 per US health literacy guidelines.
Break long sentences. Replace complex words with simpler alternatives. Use active voice. Add subheadings every 150–200 words. Keep paragraphs to 3–4 sentences max.