Flesch-Kincaid Readability Formula

The Flesch-Kincaid readability formula was designed for technical documents and is mostly applicable to manuals and forms, rather than schoolbook text or literary works. This test calculates the U.S. grade level of a text sample based on sentence length and syllable count. This test, along with Simplified ARI and New Fog Count, is part of the Navy Readability Indices collection of tests.

The Flesch-Kincaid Formula

GL = (11.8*ASW) + (.39*ASL) -15.59

Where:

GL	U.S. grade level
ASW	Average number of syllables per word
ASL	Average sentence length

Citations

Kincaid, J.P., Fishburne, R.P, Rogers, R.L. & Chissom, B.S. (1975). Derivation of new readability formulas (automated readability index, Fog count and Flesch reading ease formula) for navy enlisted personnel. Research Branch Report 8-75. Naval Air Station, Memphis, TN.