SMOG Grade

Health handouts, consent forms and medication leaflets usually arrive with a written requirement in the brief: keep the language at a sixth to eighth grade level. SMOG is the formula that field reaches for, because it was validated on health material and errs on the strict side. It returns how many years of schooling a reader needs to follow the text on a first pass.

It counts words of three or more syllables and applies 1.0430 times the square root of polysyllables times thirty divided by sentences, plus 3.1291. The thirty comes from the original procedure: sample thirty sentences, ten from the start, ten from the middle, ten from the end. This page rescales by however many sentences you paste, which is handy and makes short samples jumpy. Syllables are vowel runs, sentences are runs of period, question or exclamation marks.

Paste thirty sentences or more if you want a figure comparable to published work. The result is not rounded, so the built-in sample reads 13.81667 and the integer part is what matters. SMOG usually lands one to two grades above Flesch-Kincaid on the same text, so keep the two scales apart in a report. The coefficients are English ones. Everything runs in your browser.