Gunning Fog Index is used to estimate the readability of a sentence. Is the website gunning-fog-index.com reliable for academic research purposes? If not, what software should I use?

  • Is it really a "calculater"?
    – Alex B.
    Commented May 27, 2018 at 22:00
  • @AlexB. Isn't it? What would you call such software?
    – Juya
    Commented May 29, 2018 at 10:51
  • Shouldn’t it be a calculator?
    – Alex B.
    Commented May 30, 2018 at 3:32
  • @AlexB.You are right. It was a typo. Edited it immediately.
    – Juya
    Commented May 30, 2018 at 11:47

1 Answer 1


The website clearly does not fulfill the requirements of Reproducible Research. The algorithm is not Open Source and the implementation isn't available for inspection.

There are more problems:

  • The Website can go away without prior notice
  • The implementation of the algorithm may change without notice

When you cannot find an Open Source implementation of the Gunning-Fox index, do it yourself. After all, the formula is not overly complex (though counting sentences and counting "complex words" can be tricky).

  • I am calculating the index for +30 sentences separately. Do you know any reliable software for this?
    – Juya
    Commented May 24, 2018 at 11:45
  • 1
    Disclaimer: I have no connections to this one and I did not test it, but I think this is worth looking at: pypi.org/project/readability/0.2 Commented May 24, 2018 at 11:50
  • 1
    There's a newer version of this now at PyPi, this link should always point to the most recent version. Commented Jul 7, 2022 at 11:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.