Invented by Edward Fry, an educator and language instructor, Fry’s Readability Formula and accompanying graph is a method for determining the reading level, or difficulty, of a given piece of writing. It is based on a formula which counts the number of sentences and syllables and then plots those results on Fry’s Readability Graph (picture below).

The formula has many uses, such as assessments for school children’s reading levels. It is also sometimes used as a way to determine how accessible a document is for the public. For example, determining whether a description of a health care policy can be understood by a wide segment of the public in order to minimize misunderstanding.

Edward Fry

Born in Los Angeles, California in 1925, Edward Fry attended Occidental College and served in the Merchant Marines during World War II. After he completed college he went on to work at Loyola University in New Orleans and then as a full professor at Rutgers University in New Jersey.

While teaching reading Fry invented to readability formula as a way to measure the difficulty of a given passage of reading or a book. It became a commonly employed tool for assessing reading levels and difficulty, especially by school systems. Fry also developed a system to teach reading for the Peace Corps.

He also had a great interest in Africa and three times taught at universities in Africa. During his third stint he helped establish the University Press for Africa University in Zimbabwe. He was president of the National Reading Conference, the International Reading Association and the New Jersey Reading Association addition to being a Fulbright Scholar.

How the formula works

Fry originally developed the reading formula for high school aged material. He then went on to expand its use to primary school and eventually to college level reading material. He felt that a person’s vocabulary continued to grow during college, but such ability is contingent on the subject and the student.

The formula, which is graph based, works in five steps.

  1. Choose three 100-word passages randomly from a reading sample. Numbers, initializations, such as “Mr.” or “CEO”, are included in the word count.
  2. Count how many sentences are in each of the passages. Estimate the fraction of the last sentence to the nearest 1/10th.
  3. Count the number of syllables in each of the passages. For numbers, each one counts as one word and each numeral counts as one syllable; therefore, 1998 would be one word, but four syllables. Then fill in the following table: 
  4. When all the averages are tallied, plot the average sentence length and number of syllables on the graph below: 
  5. The area in which the averages fall is the comparable grade level for the passage. If there is a great deal of variability in the scores select new samples.

Further resources