SMOG Readability Calculator - SMOG Index

Check the SMOG index and SMOG readability score with the online SMOG Readability Calculator.

Reading Score


Reading Level


Reading Note


What Is Smog Readability?

The SMOG (Simple Measure of Gobbledygook) grade is a measure of readability developed by G. Harry McLaughlin in 1969, recommended for use in healthcare. It was developed as an alternative for the Gunning fog index.

What Is Smog Readability Formula

Here is the SMOG readability formula for a passage of at least 30 sentences.

1.0430 × square root(total polysyllables × (30 ÷ total sentences)) + 3.1291

According to the paper, Assessing the Readability of Policy Documents: The Case of Terms of Use of Online Services, here are the approximate conversion between the education level and SMOG readability score:

ScoreEducation Level
4.9 or lowerElementary school
5 - 8.9Middle school
9 - 12.9High school
13 - 16.9Undergraduate
17 or higherGraduate

How Can You Decrease Smog Readability Score?

You can decrease the score by using fewer words of three or more syllables.

What Is the Smog Readability Calculator?

This online tool can be used to calculate the Smog readability grade of a text using the formula. All you have to do is to type or paste the whole content you want to evaluate into the input above.

Text Analysis