The Fry readability graph estimates the school grade level a reader needs for a passage. It uses only two counts: sentences and syllables per 100 words. That simplicity is its strength: you can score a page by hand in minutes, with no software.
Step 1: take three samples
Pick three passages of exactly 100 words each: one from the start, one from the middle, and one from the end of the text. Skip headings, lists, and captions, since they distort the counts. If a passage has fewer than 100 words at the end, you can still use it by scaling the counts proportionally, but full 100-word samples are cleaner.
Why three samples? One sample can be unrepresentative: an introduction is often simpler than the body. Averaging three spread-out samples gives a fair picture of the whole text.
Step 2: count sentences and syllables
For each 100-word sample, count sentences to the nearest tenth. A sample ending mid-sentence counts fractionally: if the last sentence is half inside the sample, count 0.5. Count syllables for all 100 words. A practical counting rule: count vowel sounds, not letters. “Reading” has two syllables, “the” has one, “beautiful” has three.
Average the three samples. Suppose your samples give 6.0, 6.5, and 6.1 sentences, averaging 6.2, and 140, 148, and 147 syllables, averaging 145. Those two averages are the only numbers the graph needs.
Step 3: read the graph
The Fry graph plots average sentences per 100 words on one axis and average syllables per 100 words on the other. Find where your two averages meet. The region they land in is the grade level. Our example, 6.2 sentences and 145 syllables, lands around grade 7, meaning a typical seventh-grader should read it comfortably.
If the point lands in the shaded invalid zone at the extremes, the passage is too unusual for the graph, usually because sentences are extremely long or short. The graph is designed for ordinary prose, roughly grades 1 to 12, and works best on passages of at least 300 words in total.
How to use the result
If the grade is higher than your audience, shorten sentences first: splitting long sentences drops the syllable density indirectly and raises the sentence count, both of which lower the grade. Then swap long words for shorter ones. Aim one or two grades below your audience’s level for general reading, since people read for information, not for a test.
Fry measures sentence length and word length only. It does not judge ideas, structure, or vocabulary familiarity. A short, simple text about a hard topic can score low while still being hard to understand. Use it as a check, not a verdict.
Fry versus Flesch and SMOG
Each readability formula suits a different job. Fry needs about 300 words of prose and gives a grade from sentence and syllable counts, which makes it good for school texts and textbook passages. Flesch works on short passages too and gives both a grade and a 0-100 ease score, which suits web content and short articles.
SMOG uses only long words and needs a 30-sentence sample, which suits longer documents like health leaflets and manuals. When two formulas disagree by a grade or two, that is normal. When they disagree wildly, check the sample: lists, headings, and numbers distort counts in different ways for each formula.
Try it faster with the tool
You can follow every step above by hand, but the free Online Fry Readability Calculator does the arithmetic for you. Enter your numbers and it gives the answer right away, so you can check your hand calculation or skip straight to the result.
Quick tips
- Three 100-word samples: start, middle, end.
- Count sentences to the nearest tenth and all syllables.
- Shorten sentences first to bring the grade down.