What Is the Gunning Fog Index Calculator?
This online tool can be used to calculate text readability using the Gunning Fog index. Just type or paste your content into the box to get the result on the fly.
Note: No text that you enter is stored on our servers. All calculations are performed locally in your browser, so only you can access the text you've entered.
What Is the Gunning Fog Index?
The Gunning Fog Index was developed by Robert Gunning, an American businessman, in 1952 as a way to measure the readability of a text.
The formula calculates readability in terms of the number of sentences, number of words, and the number of complex words consisting of three or more syllables in a text. The lower the index score, the easier it is for readers to understand the text.
The Gunning Fog readability formula for a passage around 100 words is
0.4 × ((total words ÷ total sentences) + 100 × total complex words ÷ total words)
Here are the interpreted results:
| Fox Index | Grade |
|---|---|
| 6 | Sixth grade |
| 7 | Seventh grade |
| 8 | Eighth grade |
| 9 | High school freshman |
| 10 | High school sophomore |
| 11 | High school junior |
| 12 | High school senior |
| 13 | College freshman |
| 14 | College sophomore |
| 15 | College junior |
| 16 | College senior |
| 17 | College graduate |
How Can You Decrease Gunning Fog Index?
You can decrease a Gunning Fog score (for better readability) by using fewer words with three or more syllables. Words with three or more syllables make the passage harder to read.
Related Tools
- Flesch Reading Ease: Measure readability based on sentence length and syllable count.
- Dale-Chall Readability: Check readability using a list of familiar words.