Readability Grade Checker
Check reading grade level using multiple formulas: Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau. Free.
How to use
Four formulas, one verdict
Each formula weights different signals. Flesch-Kincaid uses sentence length and syllables. Gunning Fog penalises complex words (3+ syllables). SMOG (Simple Measure of Gobbledygook) was designed for medical text. Coleman-Liau uses character counts rather than syllables — easier for software to compute reliably. If three or more agree within 1 grade level, the result is solid. If they disagree by 3+ grade levels, the text has unusual patterns worth investigating.
Plain-language targets
UK government plain-language guidance targets grade 9 or below. US Plain Writing Act (2010) targets grade 8 or below for federal communications. Newspapers like The Sun and Daily Mirror sit around grade 7. Broadsheets like The Times and Guardian sit around grade 9-10. Academic journals sit around grade 14-18.
The Flesch-Kincaid Grade Level was developed for the US Navy in 1975 to assess training manuals. Plain-language laws in the US (Plain Writing Act 2010) require federal communications to score around grade 8 or below — most academic prose scores grade 12-16.
Different formulas weight different signals. Flesch-Kincaid looks at sentence length and syllables. Gunning Fog penalises 'hard' words (3+ syllables). SMOG was designed for medical text. If multiple scores agree, the result is reliable. If they disagree by 3+ grade levels, the text has unusual sentence/word patterns — usually worth investigating.