Flesch Reading Ease Score Calculator
Compute the Flesch Reading Ease score from word count, sentence count, and syllable count — the most widely used readability formula in English. Scores from 0 (very difficult) to 100+ (very easy) tell you the education level a typical reader needs to understand the text.
Last updated: May 2026
Compare with similar
About this calculator
The Flesch Reading Ease formula (Rudolf Flesch, 1948) is: score = 206.835 − 1.015 × (totalWords / totalSentences) − 84.6 × (totalSyllables / totalWords). The two ratios capture sentence length (words per sentence) and word complexity (syllables per word) — the two main drivers of text difficulty. Lower scores mean harder text; higher scores mean easier text. Standard interpretation bands: 90–100 = very easy, 5th-grade level; 80–90 = easy, 6th-grade; 70–80 = fairly easy, 7th-grade; 60–70 = standard, 8th–9th grade (target for most general writing); 50–60 = fairly difficult, 10th–12th grade; 30–50 = difficult, college level; 0–30 = very difficult, college graduate level; below 0 = extremely difficult (possible for legal/scientific text). Variables: totalWords from a word processor's word count; totalSentences from counting sentence-ending punctuation (. ? !); totalSyllables from a syllable-counting tool or manual count using vowel-group heuristics. Edge cases: scores can exceed 100 (very simple text like 'Run. Jump. Play.') or drop below 0 (extremely complex academic text). The formula was calibrated on English; using it on other languages produces meaningless results. It captures only sentence-length and syllable density — it ignores vocabulary familiarity, conceptual difficulty, syntactic complexity beyond sentence length, and reader background. A short-sentence text using rare technical terms can score 'easy' while being genuinely hard, and a complex-syntax text with common words can score 'hard' despite being clear to its audience. Pair with other readability tests (Flesch-Kincaid Grade Level, SMOG, Gunning Fog) for a fuller picture.
How to use
Example 1 — Plain English benchmark. A 100-word paragraph with 8 sentences and 130 syllables. Average words/sentence = 100/8 = 12.5. Average syllables/word = 130/100 = 1.30. Score = 206.835 − 1.015 × 12.5 − 84.6 × 1.30 = 206.835 − 12.69 − 109.98 = 84.17. ✓ That's an 'easy' score (80–90), 6th-grade reading level — the target for most consumer-facing writing, including news websites and instruction manuals. Example 2 — Academic prose. A 200-word abstract with 7 sentences and 350 syllables. Words/sentence = 200/7 ≈ 28.57. Syllables/word = 350/200 = 1.75. Score = 206.835 − 1.015 × 28.57 − 84.6 × 1.75 = 206.835 − 28.99 − 148.05 = 29.79. ✓ That's a 'difficult' score (30–50), college-level reading. Typical of academic writing in humanities and social sciences. To make it more accessible, shorten sentences (target ~15 words/sentence) and replace polysyllabic terms with shorter equivalents.
Frequently asked questions
What is a good Flesch Reading Ease score for general writing?
For consumer-facing writing (news, marketing, instruction manuals, websites for general audiences), aim for 60–70 — the 'standard' band, equivalent to 8th–9th grade reading level. This is the level most US adults can read comfortably. For audiences with above-average education or specialised interest (trade publications, professional blogs), 50–60 is acceptable. For broad mass audiences (tabloids, children's content, basic information for non-native English speakers), aim for 70–90. Legal contracts and academic papers often score 0–30, which is technically very difficult — and while some specialised contexts demand it, in most consumer contexts it indicates writing that excludes most readers. Many style guides (AP, Reuters, Microsoft Manual of Style) explicitly target Flesch scores in the 60s for general writing. Tools like Hemingway Editor, Grammarly, and Microsoft Word's built-in readability stats display the Flesch score alongside other readability metrics.
Why does the formula penalise long sentences and long words?
Both contribute to reading difficulty in ways measured in psycholinguistic research. Long sentences strain working memory — readers must hold subject, verb, and object relationships across more intervening text, increasing comprehension load. Each additional clause adds 5–10% to reading time. Long words (multisyllabic) are typically rarer and require more lexical retrieval effort; common English words are predominantly 1–2 syllables, while uncommon ones (often Latin/Greek origin) are 3+ syllables. The 1948 Flesch calibration found that sentence length explains about 25–30% of readability variance and syllable density another 40–50% — together capturing most of what makes text hard or easy at a surface level. The formula doesn't distinguish 'long word because complex concept' from 'long word because pretentious vocabulary' — it just measures the surface feature. Simplifying genuinely complex material requires more than shortening sentences; it requires re-framing concepts in simpler terms.
How is Flesch Reading Ease different from Flesch-Kincaid Grade Level?
They use the same two inputs (sentence length and syllable density) but combine them differently and report on different scales. Flesch Reading Ease (this calculator) gives a 0–100+ score where higher = easier. Flesch-Kincaid Grade Level gives a US school-grade number where higher = more difficult: GL = 0.39 × (words/sentence) + 11.8 × (syllables/word) − 15.59. A Flesch Reading Ease of 80 corresponds roughly to grade level 6; ease 60 corresponds to grade 8.5; ease 30 corresponds to grade 13 (college). The two are essentially inverses; researchers and writers can use whichever feels more interpretable for their audience. Microsoft Word's readability stats show both. Other widely-used readability tests (SMOG, Coleman-Liau, Automated Readability Index, Gunning Fog) use different formulas but track the same underlying variables; correlations between any two are typically 0.85+ on the same text.
What are the most common mistakes people make using readability formulas?
The first is treating the score as a complete measure of text quality — Flesch only measures sentence length and syllable density, ignoring vocabulary familiarity, conceptual difficulty, audience background, and rhetorical clarity. Good writing can score 'difficult' (long technical terms used correctly with informed readers); bad writing can score 'easy' (short choppy sentences with no logical flow). The second is gaming the formula by artificially shortening sentences and using simpler words at the cost of clarity; the formula has been criticised for incentivising 'dumbed-down' prose that loses precision. The third is using the formula on text where readability isn't the relevant concern — poetry, dialogue, technical specifications all have legitimate reasons to score 'hard'. The fourth is applying the formula to non-English text; it's calibrated for English and produces meaningless scores in other languages (use language-specific formulas like the Hungarian Flesch-Kincaid). The fifth is over-reliance on a single readability score; modern best practice combines multiple metrics with human review for the audience and purpose.
When should I not use this calculator?
Skip it for non-English text — Flesch was calibrated on English and produces meaningless scores in other languages; use language-specific readability formulas (LIX for Scandinavian languages, Indice Flesch-Vacca for Italian, FRES for German). Avoid it for poetry or song lyrics where artistic intent overrides accessibility goals. It is the wrong tool for technical specifications, legal documents, and academic papers where precision and conventional terminology are required despite their effect on readability — these naturally score 'difficult' and that's not a problem to fix. Do not use it as a sole quality metric for writing; it captures only sentence length and syllable density, missing vocabulary, logical structure, and audience-fit entirely. Skip it for assessing reading level of individual readers; Flesch measures the text, not the reader's ability — use placement tests for that. And for accessibility compliance (WCAG, Section 508), use the specific readability standards required by the regulation, which sometimes specify particular formulas and target grade levels.