A photograph of the Chicago skyline enveloped in fog

Source: Chicago-Illinois-USA-skyline-fog, Basho, Wikimedia

You learned that simple sentences can be very effective, but that too many simple sentences result in lethal choppiness. So, do you strive to write lengthy alternatives? Should you model your writing after this sentence by Thomas Hooker, father of American democracy?

Now if nature should intermit her course and leave altogether, though it were but for awhile, the observation of her own laws; if those principal and mother elements of the world, whereof all things in this lower world are made, should lose the qualities which now they have; if the frame of that heavenly arch erected over our heads should loosen and dissolve itself; if celestial spheres should forget their wonted motions, and by irregular volubility turn themselves any way as it might happen; if the prince of the lights of heaven which now as a giant doth run his unwearied course, should, as it were through a languishing faintness, begin to stand and to rest himself; if the moon should wander from her beaten way, the times and seasons of the year blend themselves by disordered and confused mixture, the winds breathe out their last gasp, the clouds yield no rain, the earth be defeated of heavenly influence, the fruits of the earth pine away as children at the withered breasts of their mother no longer able to yield them relief – what would become of man himself, whom these things now do all serve?

from Of the Laws of Ecclesiastical Polity

The 196 words of Hooker’s sentence don’t give readers a chance to catch their breath. A businessman who thought Hooker’s writing and the writing of many others was too foggy came up with a way to measure the highest grade level you would need to understand a passage on the first reading. The Gunning Fog Index measures both sentence length and word length. However, the focus in this lesson is on sentence length.

In the next exercise, you’ll read three passages and then predict their readability by grade level (1 is first grade; 12 is a senior in high school; 18 is a graduate student). Then you’ll cut and paste the passage into a calculator to compare the Gunning Fog rating to your estimate. Keep in mind that this method of determining readability is only one of many. These formulas measure surface level complexity but do not get at deeper levels of meaning. Several factors beyond word length, number of syllables, frequency of occurrence in the language, and sentence length contribute to the complexity or difficulty level of reading passages.

Follow these directions to get the Gunning Fog rating for any passage that you read on the computer. Try it a few times with text from the lesson or text from other sources:

  1. Copy the text you want to test.

  2. Open the website http://gunning-fog-index.com.

  3. Paste the text into the box and click “Calculate.”

After you have experimented on your own with Gunning Fog ratings, answer the next few questions. Then you’ll cut and paste the passage into a calculator to compare the Gunning Fog rating to your estimate.

A portrait/painting of the character Anna Karenina. She is a wearing an 18th century gown and is surrounded by envelopes and letters.

Source: Anna Karenina by H. Manizer, Henrich
Matveevich Manizer, Wikimedia

Passage 1

And therefore, deciding to divide the trousseau into two parts–a larger and smaller trousseau–the princess consented to have the wedding before Lent. She determined that she would get the smaller part of the trousseau all ready now, and the larger part should be made later, and she was much vexed with Levin because he was incapable of giving her a serious answer to the question whether he agreed to this arrangement or not.

What is the Gunning Fog rating for this selection?

a. 7.023
Try again.

b. 12.045
Try again.


An image of a postage stamp featuring the painted characters Tom Sawyer and Huckleberry Finn sitting on a rock wall.

Source: Stamp Germany 2001 MiNr2194 Tom Sawyer und Huckleberry
Finn, Gerd Aretz, Oliver Aretz fur das Bundesministerium der Finanzen
und die Deutsche Post AG, Wikimedia

Passage 2

Now he lapsed into suffering again, as the dry argument was resumed. Presently he bethought him of a treasure he had and got it out. It was a large black beetle with formidable jaws–a "pinchbug," he called it. It was in a percussion-cap box. The first thing the beetle did was to take him by the finger. A natural fillip followed, the beetle went floundering into the aisle and lit on its back, and the hurt finger went into the boy’s mouth. The beetle lay there working its helpless legs, unable to turn over. Tom eyed it, and longed for it; but it was safe out of his reach. Other people uninterested in the sermon found relief in the beetle, and they eyed it too. Presently a vagrant poodle dog came idling along, sad at heart, lazy with the summer softness and the quiet, weary of captivity, sighing for change. He spied the beetle; the drooping tail lifted and wagged. He surveyed the prize; walked around it; smelt at it from a safe distance; walked around it again; grew bolder, and took a closer smell; then lifted his lip and made a gingerly snatch at it, just missing it; made another, and another; began to enjoy the diversion; subsided to his stomach with the beetle between his paws, and continued his experiments; grew weary at last, and then indifferent and absent-minded.

What is the Gunning Fog rating for this selection?

a. 7.134

b. 12.045
Try again.

c. 14.892
Try again.

A painted mural featuring the Darling children and Peter Pan standing on a cloud.

Source: Peter Pan Mural 1, ATIS547, Flickr

Passage 3

It was the colour of milk; but the children did not have their father’s sense of humour, and they looked at him reproachfully as he poured the medicine into Nana’s bowl. “What fun!” he said doubtfully, and they did not dare expose him when Mrs. Darling and Nana returned.

“Nana, good dog,” he said, patting her, “I have put a little milk into your bowl, Nana.”

Nana wagged her tail, ran to the medicine, and began lapping it. Then she gave Mr. Darling such a look, not an angry look: she showed him the great red tear that makes us so sorry for noble dogs, and crept into her kennel.

Mr. Darling was frightfully ashamed of himself, but he would not give in. In a horrid silence Mrs. Darling smelt the bowl. “O George,” she said, “it’s your medicine!”

“It was only a joke,” he roared, while she comforted her boys, and Wendy hugged Nana. “Much good,” he said bitterly, “my wearing myself to the bone trying to be funny in this house.”

What is the Gunning Fog rating for this selection?

a. 3.134
Try again.

b. 5.703

c. 6.28
Try again.

The first passage from Anna Karenina by Leo Tolstoy has a 51-word sentence. Based on the calculation of the readability of a single passage from this notoriously long novel, you won’t be able to comprehend Tolstoy’s work on the first reading until you’re in graduate school (17.89 years of school). Given that this novel is more than 700 pages, you might not have time to read it a second time to gain complete understanding, but because it’s a great masterpiece of literature, it’s more than worth the effort.

Passage 2 from The Adventures of Tom Sawyer by Mark Twain uses a variety of sentence lengths to establish the tension of suppressed laughter. The short sentences averaged with the long ones make this passage highly readable (7.134 years of school). Of course, you still have to address uncommon words like “bethought” and “fillip.”

Short dialogue sentences in the third passage from Peter Pan make this text whisk by (5.703 years of school), but you also need to consider the author's underlying message.