Flesch-Kincaid Grade

Flesch-Kincaid Grade estimates the US school grade a reader needs to understand a text, from two things: how many words its sentences have on average, and how many syllables its words have on average. Long sentences and long words raise the grade.

It was developed for the US Navy in 1975 and is the most widely used readability formula for English. Silktide uses it for English by default, and adds 5 to the grade to give a : grade 8 is a reading age of 13.