What is the Gunning Fog formula?

Fog = 0.4 × (words/sentences + 100 × complex_words/words). Complex words have 3+ syllables. A score of 8 means 8th grade reading level required.

What is a good Gunning Fog score?

Most effective professional writing scores 8–12. Academic writing typically scores 14–20. Legal documents often score above 20, contributing to poor comprehension.

How do I lower my Fog score?

Use shorter sentences, replace 3-syllable words with simpler alternatives, and break complex ideas into shorter paragraphs.

Gunning Fog Index Calculator

Formula Definitions

The Gunning Fog Index Calculator works by applying a well-defined formula to the values you enter. Understanding the formula behind the calculation helps you interpret the result and check that your inputs are correct. Below we break down the key components that drive the Gunning Fog.

The core formula used by this calculator is:

Result = f(inputs, settings)

Each variable in the formula has a specific meaning:

inputs — Values entered into the Gunning Fog.
settings — Options, units, or parameters that adjust how the calculation is performed.
Result — Computed output for the chosen inputs and settings.

How to Use This Calculator

Enter the required values. Enter the required values into the Gunning Fog Index Calculator input fields.

Adjust settings. Adjust any settings, select applicable options, or choose units as needed.

Calculate the result. Press Calculate to compute the result using the underlying formula.

Interpret the output. Review and interpret your result using the provided context, reference ranges, or explanatory notes.

Glossary and Definitions

Input

A value entered into the calculator to be processed.

Output

The computed result returned by the calculator for the given inputs.

Setting

An option that adjusts how the calculation is performed, such as unit selection or mode.

Gunning Fog index