Readability Score Checker

The tool runs five different readability formulas on your text and shows them side by side: Flesch Reading Ease (a 0 to 100 score where 60 to 70 is plain English), Flesch-Kincaid Grade Level (the US school grade needed to read it), Gunning Fog Index (years of formal education needed), SMOG (a polysyllable-based grade for technical writing), and Coleman-Liau (a character-count-based grade that ignores syllables). Below all five the tool averages the four grade-level scores into one number and gives a label: Very Easy, Easy, Fairly Easy, Standard, Fairly Difficult, Difficult, or Very Difficult.

Five formulas instead of one because each captures something different. Flesch-Kincaid and SMOG penalise long syllable counts; Coleman-Liau cares only about characters and sentence length, so it works on text where syllable detection is unreliable (initialism-heavy technical writing, for example). Gunning Fog is the formula journalists are taught in school. Showing all five together stops you from optimising to one number and missing a problem the others would catch.

It depends on the audience. For a general consumer blog, news article, or marketing copy aim for Flesch Reading Ease 60 to 70 and grade level 7 to 9. The Sun and the Daily Mirror sit around grade 6; The Guardian sits around grade 9 to 10; The Economist runs grade 14. For a B2B SaaS landing page aim grade 9 to 11. For a legal contract or academic paper grade 14 plus is normal and not a problem.

Concrete example: paste in a 200-word email to a customer and you might get Flesch Reading Ease 72, Flesch-Kincaid grade 7.2, average sentence length 14 words. That is on target for customer-facing email. If the same email returns Flesch Reading Ease 38 and grade 14, you have written something that reads like a legal disclaimer; the tips panel will tell you to break long sentences and replace polysyllabic words. Re-run after editing and watch the score move.

The reading time estimate uses 200 words per minute, which is the average for adults reading English prose silently. A 1,000-word article comes out as 5 minutes; a 250-word product description as roughly 1 minute. Reading aloud is slower (about 130 to 150 wpm); skimming is faster (300 to 400 wpm). The number is a rough planning aid, not a stopwatch.

If your text reads slowly even though the word count is short, it usually means very long sentences or very dense sentences. The improvement tips at the bottom of the result flag the specific issue: average sentence length over 15 words, average syllables per word over 1.5, complex words above 10% of the total. Fix the flagged item, paste the rewrite, and you will usually see the grade level drop by 1 to 2 levels. The [word counter](/word-counter) will give you a more granular breakdown if you need exact totals.

Readability formulas measure surface features (sentence length, syllable count, character count) not actual comprehension. A 7th-grade-rated paragraph about quantum entanglement is still incomprehensible to a 7th grader because the concepts are hard, not the syntax. Equally, a Hemingway novel with a Flesch-Kincaid grade of 4 is not literally a children's book; the prose is just unusually clean.

The formulas were also calibrated on US English text decades ago. They work fine for British English but mishandle some specific things: hyphenated compounds get over-counted as polysyllabic, technical jargon with three or four syllables (kilometre, organisation) inflates Gunning Fog without genuinely making the text harder, and very short texts (under 100 words) give unreliable scores because there is not enough data. Treat the score as a strong hint, not a verdict.