Readability Checker
Paste your text to get Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, Coleman-Liau, SMOG, and ARI scores — all at once.
Enter text to see readability scores
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What Do Readability Scores Actually Measure?
Every readability formula boils text down to a number using just two things: sentence length and word complexity. That sounds reductive, but it works surprisingly well. Long sentences make readers work harder to track meaning. Long words — ones with three or more syllables — slow down both reading speed and comprehension. The formulas just combine these factors differently.
Flesch Reading Ease target. Readable by most adults without effort. Good for news sites, how-to articles, product pages.
The sweet spot for copy that needs to convert. Short, punchy sentences. Every word earning its place.
White papers, research summaries, technical documentation. Readers expect density and are willing to slow down.
Contracts, academic journals, regulatory filings. Fine for specialists, but inaccessible to general readers.
The Six Scores — and When Each One Matters
Running six formulas on the same text might seem excessive, but each catches something slightly different. Here's the quick breakdown:
- Flesch Reading Ease — the oldest and most widely cited. A 0-100 scale where higher is simpler. Use this as your primary benchmark for web writing.
- Flesch-Kincaid Grade Level — same formula variables, different output: a US school grade. Grade 8 content works for most adult audiences. Journalists often target grade 6-7.
- Gunning Fog Index — penalizes “complex words” (3+ syllables) more heavily than the Flesch formulas. Good for spotting jargon overload.
- Coleman-Liau Index — uses character counts instead of syllables, which makes it more consistent across different types of text.
- SMOG Index — designed specifically for health communications. If you're writing patient instructions or health content, SMOG is the one to watch.
- ARI (Automated Readability Index) — another character-based formula, developed originally for the US military. Correlates well with reading level tests.
How to Actually Improve Readability
The formulas tell you what's wrong. Fixing it is a different skill. A few things that genuinely move the scores — and also make writing better:
- Cut sentence length. If you're averaging over 20 words per sentence, start splitting. Find the comma or conjunction in the middle and make it a full stop.
- Replace long words with short ones. “Use” instead of “utilize.” “Start” instead of “initiate.” Most of the time the short version is just better.
- Switch to active voice. “The team completed the project” vs “the project was completed by the team” — same information, one fewer syllable cluster, and easier to parse.
- Explain jargon or cut it. If you must use a technical term, introduce it plainly on first use. Readers who don't know it won't look it up — they'll leave.
Frequently Asked Questions
What is the Flesch Reading Ease score?
Flesch Reading Ease is a 0-100 score — higher is easier. Scores of 60-70 are ideal for web content and general audiences. Below 30 is college-level or harder. The formula weighs average sentence length and average syllables per word.
What Flesch Reading Ease score should I target?
For blog posts and web content, aim for 60-70. Marketing copy and landing pages do better at 70-80 — the simpler the better when you want action. Academic papers sit around 30-50, and legal documents are often below 30.
What is the Flesch-Kincaid Grade Level?
Flesch-Kincaid Grade Level estimates the US school grade needed to understand the text. A score of 8 means an 8th grader can read it comfortably. Most general-audience writing should target grade 6-9.
What is the Gunning Fog Index?
Gunning Fog estimates reading difficulty by counting long sentences and complex words (3+ syllables). A score of 12 means the text needs a high school education. Scores above 17 are considered impenetrable for most readers.
How do I improve my readability score?
Three things move the needle fastest: shorter sentences (aim for 15-20 words), simpler words (one or two syllables when possible), and active voice. Breaking up long paragraphs also helps, even though it is not factored into the formulas.